With those driveline specs, I wouldn't worry about the engine at all, it's fine. I'd be looking at swapping the Powerglide / Rear Gearing - THAT'S the bottleneck. Play around with some online gear ratio calculators, like this one: https://spicerparts.com/calculators/transmission-ratio-rpm-calculator With say 25" tires and those 2.73 Rear Gears, and assuming an engine that comes on power at 2500rpm and shifts at 4500rpm, and a converter that stalls at say 1500rpm: * Powerglide "first" gear (1.76 ratio which is virtually 2nd gear in any 3-speed trans), it's a slippery slug until 1500rpm (when the converter grabs) = 25mph, and then things don't get much better until around 2500rpm, which is 40mph, and shifting at a mild 4500rpm won't happen until 72mph (I used to have a '68 Skylark with the Buick 2-speed, I feel your pain here). On the highway, 2500 in top gear is right at 71mph. * Swap in a 700R4 (same stall converter) with its 3.06 first gear and .07 OD, and things start happening a LOT faster: Converter stall happens at 14mph, shift to 2nd is at 42mph and 2500rpm = 43mph, so you're still in the engines happy powerband - this time it's in 2nd gear until 78mph, then 3rd (1:1) is 2750rpm, on up to 4500rpm = 128mph. Cruising in OD (.7) will give you 70mph = 1750rpm, not counting the converter lockup, good for another 100-200 rpm. * Then swap those Rear Gears for some say 3.08s, and: Converter stall happens at 12mph, shift to 2nd is at 36mph, and Cruise is 70mph = 1950rpm not counting lockup * Or swap them for some 3.73s, and: Converter stall happens at 10mph, shift to 2nd is at 30mph, and Cruise is 70mph = 2350 rpm not counting lockup Of course, the 700R4 with stock gears might be lugging with cruising, but maybe not with a stock engine in a light El Camino. BUT you can get whatever converter stall speed you like, and control the converter lockup a dozen different ways. We've got a '69 Chevy C10 with a stock 350, 3.73 gears, and a 700R4, and it launches itself with astonishing speed - matter of fact, I wish it had taller gears like 3.5 or even 3.08s for the mileage. Seriously, if you're going to drop $2K, I'd get a good 700R4 like these from Phoenix Trans WAY before I did anything to the engine. You'll think you added a thousand horsepower!
You guys are right, maybe i will figure something else to do involving the car, i will give him these suggestions. Because he does think a stall converter will make the car a lot quicker than it is
I thank you all for the input in steering me in the right direction in where to spend my money wisely, my greatest appreciation
