Engine Swap-305 to 350
Question:
A 383 is a SBC 350 block bored .30 over and a SBC 400 crank with the mains cut down to fit the 350s main bearing journals. With a good cam and carb or fuel injection set up you can get almost the same amount of torque as a big ol 454 but it bolts in place of a SBC. What rev limiter chip is on the 6AL ignition you have? Maybe that is your problem? Steve W. > What is a 383 CID & 400 crankshaft? And I don’t get codes in my truck too > old 85′ blazer full size 4×4. > And now that I’m asking I can never get the RPMs past 4k. Why is that it > seems that’s where the power is hiding. (But not the good mileage)
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Response:
> (Snip) > If you have a 305, that’s the source of all yer’ woes. If an oxygen poor > mixture was yer’ problem you’d be getting an 02 lean DTC. No codes, mixture > is fine and an 02 bottle won’t help. If you want to go faster and up hills > better, grab a decent 350, stroke it to 383 CID by swapping in a 400 > crankshaft and varoooommm! > Doc > What is a 383 CID & 400 crankshaft? And I don’t get codes in my truck too > old 85′ blazer full size 4×4.
Pretty sure the 85’s were CCC <computer control command> which do in fact have a really simple computer, electronic idle mixture, o2 sensor, etc and do store trouble codes. Check your exhaust work for an 02 sensor. If you find one, you have CCC. If it’s just plain old carbed, you might need to re-jet her for higher altitude operation. > And now that I’m asking I can never get the RPMs past 4k. Why is that it > seems that’s where the power is hiding. (But not the good mileage)
Dunno on that one, most stock 305’s I’ve owned/driven shift out at 4k as Regards, Doc
Response:
I didn’t put the chip in because, the ranges were 3000, 4000, 6000 and 8000. The low was to low and I would know to take my foot off the gas when it got to the high range. It was just a waste of time to put it in. When I’m in overdrive and regular drive the RPMs never get very high unless I’m in a low gear but that doesn’t get me to highway speed so I don’t down shift it. And just so I’m sure SBC means Small Block Chevy right?
– Hide quoted text — Show quoted text -> A 383 is a SBC 350 block bored .30 over and a SBC 400 crank with the mains > cut down to fit the 350s main bearing journals. With a good cam and carb or > fuel injection set up you can get almost the same amount of torque as a big > ol 454 but it bolts in place of a SBC. What rev limiter chip is on the 6AL > ignition you have? Maybe that is your problem? > Steve W. > > What is a 383 CID & 400 crankshaft? And I don’t get codes in my truck > too > old 85′ blazer full size 4×4. > And now that I’m asking I can never get the RPMs past 4k. Why is that it > seems that’s where the power is hiding. (But not the good mileage) > —–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– > http://www.newsfeeds.com – The #1 Newsgroup Service in the World! > —–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
(Snip) If you have a 305, that’s the source of all yer’ woes. If an oxygen poor mixture was yer’ problem you’d be getting an 02 lean DTC. No codes, mixture is fine and an 02 bottle won’t help. If you want to go faster and up hills better, grab a decent 350, stroke it to 383 CID by swapping in a 400 crankshaft and varoooommm! Doc > What is a 383 CID & 400 crankshaft? And I don’t get codes in my truck too
old 85′ blazer full size 4×4. And now that I’m asking I can never get the RPMs past 4k. Why is that it seems that’s where the power is hiding. (But not the good mileage)
Response:
- Hide quoted text — Show quoted text -> Ya took the words right out of my mouth Steve. A 4.3 V-6 bolts up to the > same trannies as a 350 does and fits in the same engine you’ve > said the 305 is a completely different engine <internally> than it’s big > brother the 350. Just for fun I beefed up the 305 in my 88′ > shaved the heads <made the little baby chambers even smaller!>, probably > around 9.5:1 by my best estimates, stock cam, true duals. Even with all > that work it still only compares to a hot-stock 350 and is definitely > lacking in the torque department. She’ll smoke em’ up to 20 mph or so <even > with the wimpy 2.73 gears>, but hit a nice, long 10% grade and she’s huffin’ > and puffin’. > Regards, > Doc
Is that why my blazer sucks ass going up the mountain to Idaho Springs? I thought it didn’t have enough air. Or something mechanical was wrong. Would putting a oxygen bottle in my truck to blow thicker air into the intake help any? I was wanting to try something like that in the hopes that it worked.
Response:
– Hide quoted text — Show quoted text -> Ya took the words right out of my mouth Steve. A 4.3 V-6 bolts up to the > same trannies as a 350 does and fits in the same engine > you’ve > said the 305 is a completely different engine <internally> than it’s big > brother the 350. Just for fun I beefed up the 305 in my 88′ > shaved the heads <made the little baby chambers even smaller!>, probably > around 9.5:1 by my best estimates, stock cam, true duals. Even with all > that work it still only compares to a hot-stock 350 and is definitely > lacking in the torque department. She’ll smoke em’ up to 20 mph or so > <even > with the wimpy 2.73 gears>, but hit a nice, long 10% grade and she’s > huffin’ > and puffin’. > Regards, > Doc > Is that why my blazer sucks ass going up the mountain to Idaho Springs? I > thought it didn’t have enough air. Or something mechanical was wrong. Would > putting a oxygen bottle in my truck to blow thicker air into the intake help > any? I was wanting to try something like that in the hopes that it worked.
If you have a 305, that’s the source of all yer’ woes. If an oxygen poor mixture was yer’ problem you’d be getting an 02 lean DTC. No codes, mixture is fine and an 02 bottle won’t help. If you want to go faster and up hills better, grab a decent 350, stroke it to 383 CID by swapping in a 400 crankshaft and varoooommm! Doc
Response:
– Hide quoted text — Show quoted text -> No actually they don’t tow the same load and are not nearly the same, the > 305 will always lose out to a 350. Less usable torque and that is the > important thing in an engine. Horsepower means nothing in the real world, it > is torque that does the work and guess what, the larger the engine the more > useful torque it makes. Horsepower is a mathematical expression of torque > over time. Those 4 bangers might see 1000 hp but that is at about 10,000 > rpm, now if you want to put a huge gear in your truck to use a screamer fine > but don’t bother trying to tow with it you won’t get the load started. That > is the big reason for using a diesel, for equal engine sizes they make more > torque than gas engines at equal rpms. > Steve W.
Ya took the words right out of my mouth Steve. A 4.3 V-6 bolts up to the same trannies as a 350 does and fits in the same engine said the 305 is a completely different engine <internally> than it’s big brother the 350. Just for fun I beefed up the 305 in my 88′ shaved the heads <made the little baby chambers even smaller!>, probably around 9.5:1 by my best estimates, stock cam, true duals. Even with all that work it still only compares to a hot-stock 350 and is definitely lacking in the torque department. She’ll smoke em’ up to 20 mph or so <even with the wimpy 2.73 gears>, but hit a nice, long 10% grade and she’s huffin’ and puffin’. Regards, Doc – Hide quoted text — Show quoted text -> Oh good now that we got that straightened out. But for the most part the > engines are the same. They bolt to the same trany and they fit in the same > motor mounts and they tow about the same load when they have over sized > cams > and MSD ignitions with bolt on super chargers and titainium plugs. > Of corse the I’ve heard about some rice grinders that have 1000 hp coming > out of a 4 banger. That’s impresive. > —–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– > http://www.newsfeeds.com – The #1 Newsgroup Service in the World! > —–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
No actually they don’t tow the same load and are not nearly the same, the 305 will always lose out to a 350. Less usable torque and that is the important thing in an engine. Horsepower means nothing in the real world, it is torque that does the work and guess what, the larger the engine the more useful torque it makes. Horsepower is a mathematical expression of torque over time. Those 4 bangers might see 1000 hp but that is at about 10,000 rpm, now if you want to put a huge gear in your truck to use a screamer fine but don’t bother trying to tow with it you won’t get the load started. That is the big reason for using a diesel, for equal engine sizes they make more torque than gas engines at equal rpms. Steve W.
> Oh good now that we got that straightened out. But for the most part the > engines are the same. They bolt to the same trany and they fit in the same > motor mounts and they tow about the same load when they have over sized cams > and MSD ignitions with bolt on super chargers and titainium plugs. > Of corse the I’ve heard about some rice grinders that have 1000 hp coming > out of a 4 banger. That’s impresive.
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Response:
> Bush, > Yes 305 heads will fit on a 350, depending on block type Original ,Vortec, > or SB2 a lot of parts may fit but they are not the same. 305s for instance > will usually have different valve sizes than a 350 and different valve > pocket shapes as well as the quench areas and chamber volumes. Crankshafts > have different size bearings depending on bore size. Bore size and piston > pin location very depending on CID or compression ratio. Believe me it can > make things interesting building engines if you don’t know what fits what, > ask guys who raced engines built in my shop. > Steve W.
Doc – Hide quoted text — Show quoted text -> Doc there exists several publications on Chevy engines which you need > to get, since most of these internal parts are shared (not that it > matters here we are replacing complete engine assemblies) however > when strapped for a pair of cylinder heads for a 350 several years > ago, a set off of a Volvo-Penta AQ 225 (305 cid) did the job quite > nicely. > Bush > —–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– > http://www.newsfeeds.com – The #1 Newsgroup Service in the World! > —–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Oh good now that we got that straightened out. But for the most part the engines are the same. They bolt to the same trany and they fit in the same motor mounts and they tow about the same load when they have over sized cams and MSD ignitions with bolt on super chargers and titainium plugs. Of corse the I’ve heard about some rice grinders that have 1000 hp coming out of a 4 banger. That’s impresive.
Response:
>Oh good now that we got that straightened out. But for the most part the >engines are the same. They bolt to the same trany and they fit in the same >motor mounts and they tow about the same load when they have over sized cams >and MSD ignitions with bolt on super chargers and titainium plugs. >Of corse the I’ve heard about some rice grinders that have 1000 hp coming >out of a 4 banger. That’s impresive.
they must use big k&n filters… i put one on my leaf blower and blew my neighbors house down… *g* mac http://www.aadtonline.com/Bios%20Files/mac%20davis.htm
Response:
Bush, Yes 305 heads will fit on a 350, depending on block type Original ,Vortec, or SB2 a lot of parts may fit but they are not the same. 305s for instance will usually have different valve sizes than a 350 and different valve pocket shapes as well as the quench areas and chamber volumes. Crankshafts have different size bearings depending on bore size. Bore size and piston pin location very depending on CID or compression ratio. Believe me it can make things interesting building engines if you don’t know what fits what, ask guys who raced engines built in my shop. Steve W.
> Doc there exists several publications on Chevy engines which you need > to get, since most of these internal parts are shared (not that it > matters here we are replacing complete engine assemblies) however > when strapped for a pair of cylinder heads for a 350 several years > ago, a set off of a Volvo-Penta AQ 225 (305 cid) did the job quite > nicely. > Bush
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Response:
I’ve done this, and done a fair amount of research. The ECM is identical between the two engines with the exception of the EPROM. The 350 uses a different calibration than the 305. Also, the injectors in the throttle body are not the same and the knock sensor is different between the two engines. The 4.3L and 5.7L (350) use the same knock sensor but the 305 is different. Other than that it’s a straight bolt up. Ken R. Doc there exists several publications on Chevy engines which you need to get, since most of these internal parts are shared (not that it matters here we are replacing complete engine assemblies) however when strapped for a pair of cylinder heads for a 350 several years ago, a set off of a Volvo-Penta AQ 225 (305 cid) did the job quite nicely. Bush – Hide quoted text — Show quoted text -> Isn’t the only difference between a 350 and 305 the piston size? How hard > would it be to salvage the outside parts. >different. The "outside parts" like belt-driven accessories, valve covers, >intake and TBI are identical, but the guts are completely different between >the two. >Regards, >Doc
Response:
Isn’t the only difference between a 350 and 305 the piston size? How hard would it be to salvage the outside parts. Have you ever seen a 351 in a 66′ mustang it sure looked like a big block then. Just kidding I know what your saying though. Me.
– Hide quoted text — Show quoted text -> Well, a 351 is a Ford motor and a 350 is a Chevy motor. George is talking > about a Chevy. 305 parts on a 350 is a mistake. Why not keep a 350 a 350? > Incidentally, neither a 350, nor a 351 are big blocks. Just because it > makes loud noise when a person has a loud exhaust on it doesn’t make it a > big block. > Snowman > why dont he just put 2 motors in 1. it will make him work alot quicker i > did the same to my 351 big block and put a 305 it was a lot easyer to do > that — > —- > the king of all junkyards
Response:
> Isn’t the only difference between a 350 and 305 the piston size? How hard > would it be to salvage the outside parts.
different. The "outside parts" like belt-driven accessories, valve covers, intake and TBI are identical, but the guts are completely different between the two. Regards, Doc
Response:
I’ve done this, and done a fair amount of research. The ECM is identical between the two engines with the exception of the EPROM. The 350 uses a different calibration than the 305. Also, the injectors in the throttle body are not the same and the knock sensor is different between the two engines. The 4.3L and 5.7L (350) use the same knock sensor but the 305 is different. Other than that it’s a straight bolt up. Ken R. – Hide quoted text — Show quoted text – >I just finished putting a 350 into my 97 sierra from the 305. Everything >went smooth as far a bolting right up connectors etc. >I did have the ECM sent to my local GMC dealer and they said the software is >the same for both engines but updated the software for the 350 engine 1999 >model year that was installed. >Steve > My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s > looking to probably go with a GoodWrench engine. The question is > should he get another 305 or upgrade to the 350? Is there any ECM > concerns involved with this such as the computer must be reprogrammed > or changed? Is it better just to stay with the 305? Anyone out there > done this/ been through this type swap who can give me some advice I > can give him would be appreciated. Thanks, George
Response:
I just finished putting a 350 into my 97 sierra from the 305. Everything went smooth as far a bolting right up connectors etc. I did have the ECM sent to my local GMC dealer and they said the software is the same for both engines but updated the software for the 350 engine 1999 model year that was installed. Steve
– Hide quoted text — Show quoted text -> My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s > looking to probably go with a GoodWrench engine. The question is > should he get another 305 or upgrade to the 350? Is there any ECM > concerns involved with this such as the computer must be reprogrammed > or changed? Is it better just to stay with the 305? Anyone out there > done this/ been through this type swap who can give me some advice I > can give him would be appreciated. Thanks, George
Response:
why dont he just put 2 motors in 1. it will make him work alot quicker i did the same to my 351 big block and put a 305 it was a lot easyer to do that
the king ofall junkyards
Response:
Well, a 351 is a Ford motor and a 350 is a Chevy motor. George is talking about a Chevy. 305 parts on a 350 is a mistake. Why not keep a 350 a 350? Incidentally, neither a 350, nor a 351 are big blocks. Just because it makes loud noise when a person has a loud exhaust on it doesn’t make it a big block. Snowman
> why dont he just put 2 motors in 1. it will make him work alot quicker i > did the same to my 351 big block and put a 305 it was a lot easyer to do > that
—- – Hide quoted text — Show quoted text -> the king of all junkyards
Response:
BwaHaHa…didn’t notice that earlier!
– Hide quoted text — Show quoted text -> Well, a 351 is a Ford motor and a 350 is a Chevy motor. George is talking > about a Chevy. 305 parts on a 350 is a mistake. Why not keep a 350 a 350? > Incidentally, neither a 350, nor a 351 are big blocks. Just because it > makes loud noise when a person has a loud exhaust on it doesn’t make it a > big block. > Snowman > why dont he just put 2 motors in 1. it will make him work alot quicker i > did the same to my 351 big block and put a 305 it was a lot easyer to do > that — > —- > the king of all junkyards
Response:
I was leaning to the 350 but didn’t want my friend to get into a mess screwing with the ECM. Is there somewhere he can get replacement chips for the 350? I’m sure there are ones out there with after market programming. All my engine swaps have been non-ECM (67′Chevelle, 69′Camaro and 75′Blazer a few VW’s etc) so I have no experience with those computers problems. I swapped the body on my 89′ GMC with an 84′ but just carried over my 89 ECM and it was fine. Thanks for the information guys I knew I’d get help out here. – Hide quoted text — Show quoted text -> My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s > looking to probably go with a GoodWrench engine. The question is > should he get another 305 or upgrade to the 350? Is there any ECM > concerns involved with this such as the computer must be reprogrammed > or changed? Is it better just to stay with the 305? Anyone out there > done this/ been through this type swap who can give me some advice I > can give him would be appreciated. Thanks, George >George, >You can use the existing computer and wireing harness, you just need to >switch out the PROM and CALPAK chips in the computer itself to let it know >it’s controlling a 350 and not a 305 <fuel and spark maps are quite >different>. That’s just about it! Very easy to do. 350 ALL THE WAY!! >Don’t waste yer’ time with another 305. >Regards, >Doc
Response:
Even inf you buy an aftermarket chip for the engine, you still need the CALPAK/MEMPAK chip for it. Just go to a junkyard and buy both chips from a donor vehicle. Sam
– Hide quoted text — Show quoted text -> I was leaning to the 350 but didn’t want my friend to get into a mess > screwing with the ECM. Is there somewhere he can get replacement chips > for the 350? I’m sure there are ones out there with after market > programming. All my engine swaps have been non-ECM (67′Chevelle, > 69′Camaro and 75′Blazer a few VW’s etc) so I have no experience with > those computers problems. I swapped the body on my 89′ GMC with an > 84′ but just carried over my 89 ECM and it was fine. > Thanks for the information guys I knew I’d get help out here. >> My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s >> looking to probably go with a GoodWrench engine. The question is >> should he get another 305 or upgrade to the 350? Is there any ECM >> concerns involved with this such as the computer must be reprogrammed >> or changed? Is it better just to stay with the 305? Anyone out there >> done this/ been through this type swap who can give me some advice I >> can give him would be appreciated. Thanks, George >George, >You can use the existing computer and wireing harness, you just need to >switch out the PROM and CALPAK chips in the computer itself to let it know >it’s controlling a 350 and not a 305 <fuel and spark maps are quite >different>. That’s just about it! Very easy to do. 350 ALL THE WAY!! >Don’t waste yer’ time with another 305. >Regards, >Doc
Response:
My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s looking to probably go with a GoodWrench engine. The question is should he get another 305 or upgrade to the 350? Is there any ECM concerns involved with this such as the computer must be reprogrammed or changed? Is it better just to stay with the 305? Anyone out there done this/ been through this type swap who can give me some advice I can give him would be appreciated. Thanks, George
Response:
350 all the way – Hide quoted text — Show quoted text – > My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s > looking to probably go with a GoodWrench engine. The question is > should he get another 305 or upgrade to the 350? Is there any ECM > concerns involved with this such as the computer must be reprogrammed > or changed? Is it better just to stay with the 305? Anyone out there > done this/ been through this type swap who can give me some advice I > can give him would be appreciated. Thanks, George
Response:
> My friend needs to replace a very tired 305 in his 92′ GMC 1500. He’s > looking to probably go with a GoodWrench engine. The question is > should he get another 305 or upgrade to the 350? Is there any ECM > concerns involved with this such as the computer must be reprogrammed > or changed? Is it better just to stay with the 305? Anyone out there > done this/ been through this type swap who can give me some advice I > can give him would be appreciated. Thanks, George
George, You can use the existing computer and wireing harness, you just need to switch out the PROM and CALPAK chips in the computer itself to let it know it’s controlling a 350 and not a 305 <fuel and spark maps are quite different>. That’s just about it! Very easy to do. 350 ALL THE WAY!! Don’t waste yer’ time with another 305. Regards, Doc
