250 HP Slant Six - No Turbo

ChazRam said
My 70 Swinger came with a 75 motor. I have the availability to get yet another 75 slant motor with low miles. I know the HP rating just kept dropping after 72 but how much? I heard 75 motors rated at 95 to 110 HP, is that true? I want a little kick to my car so my plan is basic. Offy 4bbl intake, Holley 390 4 bbl, Hooker Super Comp split Hedders (long tube), and a windage tray for starts. What can I expect to achieve with this in regards to HP? Additions will be a new tranny with a shift kit and a 323 grip out back. My question on all this is with this stuff on the car, the carb jetted to run, the true dual exhaust, and all the other stuff I listed can I get a ET slip somewhere in the 14s at like 90mph. Thats all I want. I want to drive the car on the street without all the hassle of a high HP motor, (been there and done that) and just want a decent cruiser. Will this work?? Thanks.
Chas.

Pretty much all of the differences between a '75 and a '70 are the way they measured horsepower, carb jetting, and the distributor advance curve. You'll need a cam, more compression, distributor recurve, and lower gears to get to your goal most likely, and I'd also add oversized valves and a little port work. It's not just the 1 bbl carb holding it back - but you aren't giving up anything by going with a smog mill either. Mopar isn't Chevy; they didn't ruin their cylinder heads to pass emissions tests. :)

Yes, it is a daily driver. That's ok though, my other car is a single digit MPG'er as well.

With all the goals you're stacking on top of each other - big horsepower numbers, naturally aspirated, and now daily driver - I'd definitely go EFI. Even a very docile engine can start better and run more smoothly on EFI, and on a high strung race motor the difference is even bigger.

You're setting very ambitious goals for yourself. I'll try to put what Vynn3 was saying with more tact: You've set a difficult goal, so research it well and try to get advice from as many gurus with more experience as possible. This will be quite a challenge, but it can be rewarding to pull it off.