Big Block help
Thread Starter
Le Mans Master
Joined: Feb 2001
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From: The problem is all inside your head she said to me.
Big Block help
I posted over in the motor section but i know there are a lot of BBC guys here
1972 SS Chevelle 402 original car with build sheet. Well Original except the hot rod items.
Problem wiped cam so we need to rebuild it. It never was that strong even with all the usual mods, 830 demon, vic jr, long block of unknown build, headers 3200 stall turbo 400, 4.11's Now I know nothing about a BBC. I just built my own roller 355, but know nothing about a BB. Would it be possible to get 450hp out of this? If so what heads, cam, and pistons would it need? I took this out for my brother over a year ago, and it's been at another guys house for months. Looks like now I get it. I'd like to help my brother and produce a good engine. Thanks for any help as I could not tell you what is a good or bad part for a BBC.
Thanks Gordon.
1972 SS Chevelle 402 original car with build sheet. Well Original except the hot rod items.
Problem wiped cam so we need to rebuild it. It never was that strong even with all the usual mods, 830 demon, vic jr, long block of unknown build, headers 3200 stall turbo 400, 4.11's Now I know nothing about a BBC. I just built my own roller 355, but know nothing about a BB. Would it be possible to get 450hp out of this? If so what heads, cam, and pistons would it need? I took this out for my brother over a year ago, and it's been at another guys house for months. Looks like now I get it. I'd like to help my brother and produce a good engine. Thanks for any help as I could not tell you what is a good or bad part for a BBC.
Thanks Gordon.
Last edited by INMYBLOOD; Jun 3, 2010 at 02:26 PM.
Le Mans Master
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From: columbus oh
Drifting
Joined: Dec 2005
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From: Valrico Florida
Unstreetable to some is streetable to others. Use of pump gas would be the determinate for me. Iron or aluminum heads? Use of an automatic or manual transmission makes a difference. How much stall speed or what kind of clutch can you live with? There are a number of good publications available. If you are stuck with specific components, stick the information in one of the better desk top dyno programs. Most would start with the performance desired then build the engine needed to meet the demand. For a street engine, I would try to maximize the area under the torque curve instead of shooting for a peak number.
Last edited by Vogie; Jun 3, 2010 at 03:36 PM.
Advanced
Joined: May 2010
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From: Quartzsite Az
If your willing to spend the money, why not upgrade to a 427 block.. I would think part availability would be better and you have more options.. I know this wasn't your questions but if your bound and determined to use that block I guess you could buy a set of aluminum heads and maybe put a new crank, rods or pistons and go from there.. I have a desk top dyno.. I can ATTEMPT to email it to you if you like??
Advanced
Joined: May 2010
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From: Quartzsite Az
Man your talking .125", that's quite a bit.. I'm sure you guys know a lot more than me when dealing with these smaller cubic inch motors but I'm afraid to go that far on a standard 4.250 block.. I've done it in a dragboat and it lived for about two season and then it had a cylinder wall fail.. I know street vs drag racing are to different applications but would you go that far on a street motor? Curious and learning, that's all!!!
Pro
Joined: Feb 1999
Posts: 735
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From: Myrtle Beach South Carolina
450hp should be easy with a .030 over 396.
We did 435hp with 10.8 CR, stock L78 cam, balanced rotating assembly, ported heads/manifolds and CC'd heads. I have the Dyno sheets to prove it.
So if 435 can be had with a basically stock setup, 450 is not that unreasonable.
We did 435hp with 10.8 CR, stock L78 cam, balanced rotating assembly, ported heads/manifolds and CC'd heads. I have the Dyno sheets to prove it.
So if 435 can be had with a basically stock setup, 450 is not that unreasonable.
Thread Starter
Le Mans Master
Joined: Feb 2001
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From: The problem is all inside your head she said to me.
Well I talked with him and he's considering or should I say does not mind switching to a 454 or more. I guess he's not pressed to keep the original block in it.
Well the car has 4.11's and a 3200 stall already. I figured 400 CI asking for 1+hp/ci was not asking alot. We were considering a set of AL heads, roller cam and pistons to match but wondered if anyone already had a combination that works.
Thanks for all the info so far.
Gordon
Well the car has 4.11's and a 3200 stall already. I figured 400 CI asking for 1+hp/ci was not asking alot. We were considering a set of AL heads, roller cam and pistons to match but wondered if anyone already had a combination that works.
Thanks for all the info so far.
Gordon
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Drifting
Joined: Dec 2005
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From: Valrico Florida
The possible combinations are significant. The only other comments I would have is that each component needs to match the others. Don't cam beyond the capability of the heads flow or compression ratio. Oppositely, don't use high compression and a small cam. Don't over-carb. Build the bottom end to withstand the worse beating you anticipate. Common opinion is that cast components and a two-bolt block is good to around 5000 RPM. Like I said before, figure out what you want the engine to do, then build the engine you need to do the job. I hope I haven't insulted you with these basic comments. Good luck with your project. I'd be interested in hearing how your project goes.
Last edited by Vogie; Jun 3, 2010 at 06:46 PM.
Advanced
Joined: May 2010
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From: Quartzsite Az
The possible combinations are significant. The only other comments I would have is that each component needs to match the others. Don't cam beyond the capability of the heads flow or compression ratio. Oppositely, don't use high compression and a small cam. Don't over-carb. Build the bottom end to withstand the worse beating you anticipate. Common opinion is that cast components and a two-bolt block is good to around 5000 RPM. Like I said before, figure out what you want the engine to do, then build the engine you need to do the job. I hope I haven't insulted you with these basic comments. Good luck with your project. I'd be interested in hearing how your project goes.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Man your talking .125", that's quite a bit.. I'm sure you guys know a lot more than me when dealing with these smaller cubic inch motors but I'm afraid to go that far on a standard 4.250 block.. I've done it in a dragboat and it lived for about two season and then it had a cylinder wall fail.. I know street vs drag racing are to different applications but would you go that far on a street motor? Curious and learning, that's all!!!
Advanced
Joined: May 2010
Posts: 81
Likes: 0
From: Quartzsite Az
yup!! you can safely do it with the right # blocks that were early production models....they had to pass the "pencil" test.....you would remove a freeze plug and see if a pencil would pass between the water jackets....sounds mickey mouse but there were only a few # blocks that would do it......
Le Mans Master
Joined: Feb 2001
Posts: 6,317
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From: Ocala FL
Most likely the 402 has oval port heads and a hydraulic lifter cam. many were around 325 hp so you have some work ahead to get to 450. You need more cam. In fact, you will need a lot of cam if you are staying hydraulic. The 390 hp hydraulic cam from a 427 will be decent for most street use but will be 400 hp tops. With the oval port heads, you are not going much over 400 hp without some serious port work.
Still, the rectangular port heads will have lower torque on the bottom end for the street, making them not so street friendly. That and a 425 hp solid lifter cam will bring you easily over 400 and closer to the 425 range if your compression is up there (11:1).
Of course, higher compression on a big block makes getting gas a problem as they are more prone to detonation than a small block.
The recommendation to go to the Chevelle forum is a good one as they will be actively using them.
Still, the rectangular port heads will have lower torque on the bottom end for the street, making them not so street friendly. That and a 425 hp solid lifter cam will bring you easily over 400 and closer to the 425 range if your compression is up there (11:1).
Of course, higher compression on a big block makes getting gas a problem as they are more prone to detonation than a small block.
The recommendation to go to the Chevelle forum is a good one as they will be actively using them.
Race Director
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From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
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If he's starting from scratch with a new build....a 496 is just as easy to do as anything. That really helps get a Chevelle moving. For a complete deal for a great price I'd check with Mark Jones aka Vortecpro. Do a search in the C-3 section for the iron oval port, hyd roller 650 HP motor he just did for Alan. I've been to his shop...top notch machine work and easy to work with. Tell him Jim sent you.
http://www.vortecproperformance.com/index.html
Otherwise...450HP can be had with oval ports and a flat tappet cam pretty easily. I'd stay away from the rectangular port stuff unless you really plan on screaming it.
JIM
http://www.vortecproperformance.com/index.html
Otherwise...450HP can be had with oval ports and a flat tappet cam pretty easily. I'd stay away from the rectangular port stuff unless you really plan on screaming it.
JIM
Last edited by 427Hotrod; Jun 4, 2010 at 08:14 AM.
Thread Starter
Le Mans Master
Joined: Feb 2001
Posts: 8,017
Likes: 2
From: The problem is all inside your head she said to me.
If he's starting from scratch with a new build....a 496 is just as easy to do as anything. That really helps get a Chevelle moving. For a complete deal for a great price I'd check with Mark Jones aka Vortecpro. Do a search in the C-3 section for the iron oval port, hyd roller 650 HP motor he just did for Alan. I've been to his shop...top notch machine work and easy to work with. Tell him Jim sent you.
http://www.vortecproperformance.com/index.html
Otherwise...450HP can be had with oval ports and a flat tappet cam pretty easily. I'd stay away from the rectangular port stuff unless you really plan on screaming it.
JIM
http://www.vortecproperformance.com/index.html
Otherwise...450HP can be had with oval ports and a flat tappet cam pretty easily. I'd stay away from the rectangular port stuff unless you really plan on screaming it.
JIM
Last edited by INMYBLOOD; Jun 4, 2010 at 10:21 AM.
Thread Starter
Le Mans Master
Joined: Feb 2001
Posts: 8,017
Likes: 2
From: The problem is all inside your head she said to me.
If he's starting from scratch with a new build....a 496 is just as easy to do as anything. That really helps get a Chevelle moving. For a complete deal for a great price I'd check with Mark Jones aka Vortecpro. Do a search in the C-3 section for the iron oval port, hyd roller 650 HP motor he just did for Alan. I've been to his shop...top notch machine work and easy to work with. Tell him Jim sent you.
http://www.vortecproperformance.com/index.html
Otherwise...450HP can be had with oval ports and a flat tappet cam pretty easily. I'd stay away from the rectangular port stuff unless you really plan on screaming it.
JIM
http://www.vortecproperformance.com/index.html
Otherwise...450HP can be had with oval ports and a flat tappet cam pretty easily. I'd stay away from the rectangular port stuff unless you really plan on screaming it.
JIM
Thanks Jim he called Mark and ordered one. He went with his new 500hp model.
Race Director
Joined: Jan 2000
Posts: 13,015
Likes: 2,260
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
I don't think you'll be disappointed!
For everyone else...he's in Colorado Springs...but he seems to have decent pricing on shipping too.
JIM
For everyone else...he's in Colorado Springs...but he seems to have decent pricing on shipping too.
JIM
Thread Starter
Le Mans Master
Joined: Feb 2001
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From: The problem is all inside your head she said to me.
