OK I'll start with Full race A15 SCCA GT-Lite car, 156 HP at the wheels. I would expect stock A15 to be 50-55 at the wheels.

Next my A12GX engine with 10-1 compression, ports cleaned up and manifold gasket matched, FCR flatslide carbs, 280 duration .460 valve lift, header, 14lb flywheel is no at about 80 WHP (with GX cam was 73 RWHP). Mostly used parts except rings bearings and Gaskets. Cost $1268

My A15 build is going to be around $1500 give or take a $100. I'll be using the GX head with FCR carbs and header off the A12, I picked up used JE piston set from PJZ, will send cam out for regrind (both cams I have are single gear) The goal is 100 WHP or better, but keep the motor making power in the 3000-7500 range instead of A12's 4500 - 8200.

Just to rough out some numbers:

If you clean up the ports yourself, use the thinner GX head gasket, have the cam reground, and add a used weber DGV style carb I'd bet you would add 12-15HP over stock. 70 at the wheels? Shop carefully and figure $600.

Next jump would be adding some pistons to up compression around 10-1 and finding some side draft carbs of some sort, I managed to find my flat slides with manifold cheap even with extra Jets and dyno run it only added up to $400. If you can find a $100 set of used pistons as I did and they fit without machine work, you could get to the 100 WHP mark the $1500 as I've planned.

Getting beyond on that will start to get very expensive, I would expect past the 100-110 RWHP mark to start costing $800-1000 for every 10 horsepower. (full race engines easily cost 10K)

My numbers don't factor in any labor as I do my own work.................I would expect the labor to double the cost, if not more.


My opinion, 120 WHP max for a street car (non turbo), beyond that and it probably would suck in any kind of traffic.

For fun I'll say the Holy Hand Grenade of Antioch Turbo Rod Flinger A-series top fuel drag motor probably could make 180 at the wheels maybe even 200................if you could bear watching $15,000-30,000 engine go kablamo.


Tom