I have a 72 convertible, 4-speed and 3:36 rear.

I am starting to think about overhauling my L-48. The car is a numbers matching engine/trans etc. and I want to maintain a stock look and keep the stock powerplant.

Having said all that, I would like to get the most performance that I can from it, keeping my vacuum parts working and on pump gas.

My thoughts are as follows:

Bore .30 over and use Keith Black Hyperutetic pistons and raise compression to 9 - 9.3 to one.

Use existing heads after having them professionally worked and larger valves 2.02 and 1.90 installed.

Comps cams 268H

Edelbrock performer intake

Edelbrock 750 carb (modeled after the quadrajet)

Dynomax headers with stage eight fastenings to 2 1/2" exhaust (what gaskets are reccomended)

MSD6AL Distributor

New clutch and throw out bearing.

Cam, distributor, Intake and carb I already own, and would like to use.

I appreciate any input, I am stuck on keeping it stock and using the exisiting heads. Headers, distributor and intake I can return to stock in short time when and if I sell. My main questions are head work, pistons, and cam set up.

Thank you

 

Appears you have a pretty good setup in mind. Might want to consider raising compression just a little but keeping it under 10:1. My best guess using my "hillbilly dyno" is that you should be about 350+HP.

 

Only thing I see you might not like is you off the line acc with the 3.36 rear but it shouldn't be horrible.

 

Looks good...I'm assuming you'll have the bottom end of the engine redone while you're at it. The only thing I see that will ruin your goal of a "stock look" are the headers. Perhaps you could port-match the original exhaust manifolds. (Perhaps Ganey will chime in on this one...)

 

I have rebuilt my L48 almost the same (buying rebuilt kit from Summit):

KB hypereutektic pistons, flat, stock rods
original cast heads (...487X), retaind the stock valve-size 1,9/1,5 for better throttle response, decked to achieve 70cc chambers, ported them to my Holley Contender intake, SCE copper head gasket,
CompCams 268, stock hydros, double-roller timing chain, matching comp cams valve springs and new locks and retainers, srew-in rocker studs,
stock Melling M55 pump (forget the HV-pump)
CompCams roller tipped rockers
New Rochester Quadrajet - the best carb I have ever had.
HEI distributor (with mechanical tach drive)
CR 9,3:1, 300 hp with 2,5" chambered exhaust and headers

Tips:
1. When they decked my block, they "wiped" of my engine code.... stupid me!! Tell the machinist
2. The cast heads in combination with this cam (produces dynamic pressure of 184 psi with my setup) results in a tendency for the engine to detonation as they do not dissipate the heat so well. I am using a 160-thermostat and 98 Octan (Germany... in US 95 should do) fuel to avoid pinging.
3. Upgrade the ballancer to 8" as this amount of power seems to destroy the stock 6,5" damper - my outer ring started slipping and my timing was way off until I realized.

I am very pleased with the performance and with the Rochester, gas-mileage and throttle-response is excellent!

Regards,
Thomas



[Modified by V8yunkie, 3:26 PM 3/2/2004]