300 c.i. Questions
All engines, 240/300 carb or efi, used the same camshaft, from the beginning to the end.
Its safe to say all cylinder heads flow about the same, stock. Main difference is the carb engines used studs and the efi used pedastel mount. The efi 300 head and 240 have smaller chambers as mentioned. The carb 300 head has a open chamber design, this allows for easier flow potential. If your looking for a stock engine, the efi 300 would be great for a daily driver, the chamber offers a swirl to the incoming air/fuel which allows less timing to be used. However, from a performance perspective, it sux, as the intake valve is shrouded horribly in stock trim, it would take some massaging to make it flow, as well as a carbd 300 head. The efi heads are also prone to crack, another downside.
Carb engines used a single outlet exh manifold, efi used dual 3 to 1 manifolds, this is a definite improvement over the single outlet exh manifold...however....you can get long tube headers for a little over a hundred (hedman) and they would be more ideal for not alot more money.
Offenhauser and clifford performance is your only source for aftermarket intakes.
Any header company is likely to have a header for your truck.
Any camshaft company can offer a camshaft. They all list their camshafts with the ideal operating range, its a no brainer, pick the one that falls into your driving habits. Believe it or not, one offers a hydraullic roller cam, not cheap. A couple offer mechanical roller camshafts.
crane is the only source I can think of for roller rockers.
The stock valves are something like 1.75 intake and 1.56 exhaust. The exhaust valve is real close to the standard 1.6 that most people use when upgrading the exh valves, so Id stick with stock to save some cash, unless it needs to be opened further. 1.94 is a good choice for the intake side on the 240 or 300 carb head....you could put the larger valve in the efi head but youd spend a couple days grinding the hell out of the combustion chamber...not worth it IMO, major drawback to this head.
The only other thing you should look out for, is some 300's had forged cranks, most had cast. There is no real way to tell which engine had which, you have to put the crank in your hand and look at key differences to distinquish which is which, if I remember right, an easy way to tell, the cast had casting lines the steel do not...other than that, some folks find a spot and take a drill bit to it, the cast will crumble, the steel will draw up material into something of a curl like a pigs tail. You need to search to verify this but I believe it to be correct. With all that said, frenchtown flyer drag races these old engines and hes said time and time again that the cast is extremely strong and as far as street engines go, it would work fine. I think some have even gone as far as saying they ware good to 400~500hp.
As far as transmissons go, the inline engine and the SBF share the same pattern, if it goes behind a small block, it will go behind your engine.
efi engines used phenolic gearsets (dense plastic of sorts), so should you choose to use an efi block, pick up a gearset intended for a carb engine pre 80 to be safe, they'll be metal. Some gearsets are fine and some course teeth. Fine is weaker than the course, so if given the option, choose course. If youd like to degree your camshaft, then opt for an adjustable timing gearset (cloyes).
Good luck




