While this might be an apples to oranges (carburated ’83 vs. more modern ’91) comparison, I thought you might like to know how a new top end (CAM, intake, heads) worked for me. With help from this forum, I guestimate the top end added 75-80HP (at wheels) and many smiles.
*Edelbrock Heads: Performer RPM, non-emissions SBF 60229 with 60cc chamber volume. 9.3:1 CR.
*CompCams valve train: XTREME Energy (35-238-3 XE262H) camshaft, Magnum (1442-16) 1.6:1 roller tipped rocker arms, hydraulic lifter set (832-16), Magnum (7632-16) 6.800” hardened push rods, double roller steel gear timing set (2120).
*Air/fuel system: Edelbrock Intake manifold (7121) Performer RPM, Edelbrock (1905) AVS2 650CFM carburetor.
At today’s prices the above might cost you $2500-$3000 if you shop at Summit Racing. 10 years ago, I spent less but my wife never fails to let me know it cost much more than I originally thought. Additionally, some other facts about my build:
*Bottom end: Stock block and crank. Bored 20 mils over, polished crank. Rotating assembly (crank, flywheel, damper) dynamically balanced for new pistons, rings, rods, etc.
*Exhaust: MAC exhaust with 1.5” shortie equal length headers, X-pipes, Flowpath mufflers and 2.5” dual exhaust (This MAC exhaust helps the smile factor).
This car was rated at 175BHP new with single exhaust. Probably 275-280 BHP now. I still have a tall 308 gear in the 7.5” back end but this car is still a blast when winding 1st, 2nd, 3rd up to 6000 RPM. I take it easy on take off and shifts to preserve my 225k mile T5. A 373 would be a blast and a bit easier on the old T5.