Here is the skinny on that Pontiac 250 cubic inch OHC engine as a possible solution, direct from Primatech, who specialzies in them:
"To meet your requirement of 300 crank horsepower, we would recommend a Stage 2 OHC Stroker. The stroker increases the CID from 250 to 271 or 275. With the stage 2 cam, some serious head porting and our OHC header, you should be able to get at least 315 FWHP on premium pump gas. Should you choose to run higher octane racing fuel, the HP number can go up - but that may be defeating the spirit of the rules. In order to exceed 400 HP, some form of forced induction would be required.
A normally aspirated. Turn-key, complete Stroker will run about $7500. Quite a bit more than the equivalent crate SBC. We have a customer running an OHC in his ’53 Sedan delivery. He is unable to run our header due to the body mount location in the engine area. Whether this is true or not of your ’55 pick-up remains to be seen. We can not predict your success with anyone else’s header(s).
Best regards,
Quenton Olson
Primatech Motorsports "
$7500 and busting a gut to hit the minimum 300 hp power level seems like a less than great solution. In addition, if this engine breaks, you don't get repairs or parts at the nearby GM dealer! Plus, these engines have a habit of eating camshafts with notable frequency, due to the way the OHC area is lubed.
Oh well, we asked and investigated, and that is what this step of the project is about.
Jim G
