Rebuild Question
Thread Starter
Racer
Joined: Jul 2006
Posts: 277
Likes: 0
From: Big Spring TX
Rebuild Question
Looking to rebuild the engine sometime in the future, pretty sure it is the stock motor.
I know I want to smooth the block and turn it into a 383, also know that I want to keep the stock block in there, even if it's a 2 bolt.
Not sure wether to put in a flat tappet or roller cam in there though.
Anyway, on to the real thing I'm wanting an opinion on. Should I port and polish the heads myself and leave them on there? To not only keep it numbers matching, but since I am going for a sleeper look as well, or should I not even worry about the heads and just slap on a pair of aluminum heads? I'm not gonna make it a pure beast of an engine, since so much runs off of vacuum on our beloved c3's after all, can't really even cam it that high, so a 500hp 383 isnt my goal. I know I could paint the aluminum heads orange and all, but dont really like that look. I always thought aluminum heads should be shown off. Completely disregarding the fact I plan on painting the edelbrock intake I plan on putting on there orange however lol.
Anyway, which would you, if you were a potential buyer of the car see?
I know I want to smooth the block and turn it into a 383, also know that I want to keep the stock block in there, even if it's a 2 bolt.
Not sure wether to put in a flat tappet or roller cam in there though.
Anyway, on to the real thing I'm wanting an opinion on. Should I port and polish the heads myself and leave them on there? To not only keep it numbers matching, but since I am going for a sleeper look as well, or should I not even worry about the heads and just slap on a pair of aluminum heads? I'm not gonna make it a pure beast of an engine, since so much runs off of vacuum on our beloved c3's after all, can't really even cam it that high, so a 500hp 383 isnt my goal. I know I could paint the aluminum heads orange and all, but dont really like that look. I always thought aluminum heads should be shown off. Completely disregarding the fact I plan on painting the edelbrock intake I plan on putting on there orange however lol.
Anyway, which would you, if you were a potential buyer of the car see?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
To take advantage of the increase in cubic inches you need to let it breathe. If you have lots of time you can clean up the iron heads and help a little bit. Be aware that it's long slow process and unless you've done a port/polish many times it's going to be tough to get all the ports matched and for best efficiency they need to flow the same. That alone would drive me to alumimum heads.
As far as paint, a layer of paint insulates. Keeping the heat in will decrease efficiency. It's your car. Do it your way. So don't let anyone tell you different.
As far as paint, a layer of paint insulates. Keeping the heat in will decrease efficiency. It's your car. Do it your way. So don't let anyone tell you different.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The L-48 heads have smaller valve diameters than you need for the 500HP required. I don't think there is anyway to get there...unless you want to do nitrous. You should plan on new aluminum heads, matching cam, roller lifters, headers and the block machining work required, if you want to use your existing components. It would be better to 'mothball' your stock engine and purchase a 500HP crate engine complete. That way, the engine components would already be matched appropriately and you would end up with a warranty on the engine. That method would also minimize the downtime required for the work.
Thread Starter
Racer
Joined: Jul 2006
Posts: 277
Likes: 0
From: Big Spring TX
Oh I'm not interested in 500hp. Just wanna turn the stock block into a 383 with a cam with about .500 lift the limiting factor is since the car has so much stuff that runs off of vaccum.
I'm probably not even going to slap headers on it and keep the stock ram horns.
I can do the port work myself, but after I spend all the money on machining on the old cast irons I kinda thought I would be at aluminum head price anyway.
I'm probably not even going to slap headers on it and keep the stock ram horns.
I can do the port work myself, but after I spend all the money on machining on the old cast irons I kinda thought I would be at aluminum head price anyway.
Instructor
Joined: May 2009
Posts: 243
Likes: 0
From: salisbury missouri
383 kit
alluminum heads (no paint) biger the valves and runners the better it will be.
roller cam (not to big)
roller rockers
if i was a potential buyer i would want the cast heads to leave with me when i pick up the car.
it would be a waste of time trying to make those stock heads breath good enough for that moter-i agree with timat on that
alluminum heads (no paint) biger the valves and runners the better it will be.
roller cam (not to big)
roller rockers
if i was a potential buyer i would want the cast heads to leave with me when i pick up the car.
it would be a waste of time trying to make those stock heads breath good enough for that moter-i agree with timat on that
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Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
If this is the numbers-matching engine and you ever think you'd want to sell it as a numbers-matching car, set aside the original engine and build something up from scratch.
The best overall approach for a budget solid-performing street 383 is using a late-model roller-cam block. They're relatively cheap, the bores are usually in great shape and you can almost always reuse the roller lifters and valley spider. A decent cast-crank 383 assembly with hypereutectic pistons shooting for 9.5 - 10 CR, overhaul the Vortec heads and put in a decent aftermarket hydraulic roller cam. Top it with a good dual-plane and carb, and you're right at 1 HP/CID flywheel or a bit better.
If you really want to build up from your existing engine, then the existing heads must go
They have the D-shaped "smog" chambers and absolutely dismal flow. Go with the same cast/hypereutectic rotating assembly, a decent set of aftermarket heads in the 180cc range and a mild cam. This will all bolt up to your existing intake, carb and exhaust manifolds and make around 340 FWHP - but some outstanding torque.
If you're going to use exhaust manifolds, I would just do a straight 355 overhaul vs. building a 383.
These are real general answers to real general questions
The best overall approach for a budget solid-performing street 383 is using a late-model roller-cam block. They're relatively cheap, the bores are usually in great shape and you can almost always reuse the roller lifters and valley spider. A decent cast-crank 383 assembly with hypereutectic pistons shooting for 9.5 - 10 CR, overhaul the Vortec heads and put in a decent aftermarket hydraulic roller cam. Top it with a good dual-plane and carb, and you're right at 1 HP/CID flywheel or a bit better.
If you really want to build up from your existing engine, then the existing heads must go
They have the D-shaped "smog" chambers and absolutely dismal flow. Go with the same cast/hypereutectic rotating assembly, a decent set of aftermarket heads in the 180cc range and a mild cam. This will all bolt up to your existing intake, carb and exhaust manifolds and make around 340 FWHP - but some outstanding torque.If you're going to use exhaust manifolds, I would just do a straight 355 overhaul vs. building a 383.
These are real general answers to real general questions