which heads / intake package?
Thread Starter
Instructor
Joined: Jul 2005
Posts: 124
Likes: 0
which heads / intake package?
I've got a '78 with an L48.
When I bought it, the previous owner had installed a custom full dual exhaust system, headers to tailpipe. He also told me the cam is not stock, though I dont know the specs so it. The engine has about 115K miles, but it has been rebuilt. It still has the stock Quadrajet carburetor
I'm wanting to upgrade the engine with new heads and intake manifold. Which would you recommend? I'm thinking of going with aluminum, but I'm open to suggestions. Would I need to know the specs of the cam to determine the best combo?
Thanks
When I bought it, the previous owner had installed a custom full dual exhaust system, headers to tailpipe. He also told me the cam is not stock, though I dont know the specs so it. The engine has about 115K miles, but it has been rebuilt. It still has the stock Quadrajet carburetor
I'm wanting to upgrade the engine with new heads and intake manifold. Which would you recommend? I'm thinking of going with aluminum, but I'm open to suggestions. Would I need to know the specs of the cam to determine the best combo?
Thanks
Burning Brakes
Joined: Aug 2006
Posts: 1,155
Likes: 0
From: San Diego California
You havent provided enough information- and you may not know enough about your engine for a really good opinion. However, I'll take a stab at this with some speculaton. If we assume that you have a basically stock L48 that runs well, and that you want to use it as a street car- not for drag racing, and that you dont want to spend a lot more money to pull the engine apart to inspect or rebuild it, then a good selection for intake manifold would be the Edelbrock aluminum Performer- with or without EGR, depending on your smog requirements; and the Edelbrock aluminum Performer heads- 64cc, for increased compression. However, if your gonna spend about $1300. for these parts, I would spend a little more to swap in a new mild perormance cam and lifters, and maybe more, to be sure you're getting the additional power you want. Thats what I did with the rebuild of the L48 in my 80 vette.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I've got a '78 with an L48.
When I bought it, the previous owner had installed a custom full dual exhaust system, headers to tailpipe. He also told me the cam is not stock, though I dont know the specs so it. The engine has about 115K miles, but it has been rebuilt. It still has the stock Quadrajet carburetor
I'm wanting to upgrade the engine with new heads and intake manifold. Which would you recommend? I'm thinking of going with aluminum, but I'm open to suggestions. Would I need to know the specs of the cam to determine the best combo?
Thanks
When I bought it, the previous owner had installed a custom full dual exhaust system, headers to tailpipe. He also told me the cam is not stock, though I dont know the specs so it. The engine has about 115K miles, but it has been rebuilt. It still has the stock Quadrajet carburetor
I'm wanting to upgrade the engine with new heads and intake manifold. Which would you recommend? I'm thinking of going with aluminum, but I'm open to suggestions. Would I need to know the specs of the cam to determine the best combo?
Thanks
This is a Vortec swap. It's becoming very popular, and an L48 with free flowing exhaust will see close to a 100 HP gain so long as internals are in good shape.
First, before it's torn down, do a leak down test and a compression test. How long ago was the motor rebuilt?
Find yourself a set of Vortec heads, from a 350, found in most late model trucks and SUVs. There are only two castings, and both are fine for you.
You will need a Vortec manifold, and you can get the Edelbrock Performers on Ebay for a little over $100.
Have the heads machined for stiffer springs, shooting for .480-.490.
Get this cam and lifter combo and replace timing set if it's stretched a little.
http://store.summitracing.com/partde...3&autoview=sku
You might need a different throttle cable bracket and you'll want all the usual goodies when refreshing a motor. Seals, gaskets, proper torque specs, and follow it all up with new plugs, wires, carb tune, and timing.
I can help you find some used Vortec heads from a salvage yard near you if you PM me your ZIP code.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 124
Likes: 0
Yeah, I want the car for street, not all-out drag performance. But i'd still like at least around 300hp, if not 350.
What kind of power increase or output (at the wheels) would I be looking at with the aluminum heads and intake, vs the Vortec heads and intake, given that I already have the headers and exhaust?
PJ
What kind of power increase or output (at the wheels) would I be looking at with the aluminum heads and intake, vs the Vortec heads and intake, given that I already have the headers and exhaust?
PJ
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