Swirl Port Heads

Tech Question


Shaun Miller, Ankeny, IA, 1974 Dodge Challenger 360

Hello sir. I have a 74 Challenger, 360, 4spd, 3.55 sure grip,bored 40, KB 107 pistons, hooker headers, MP 284 duration, 484 lift cam with68 overlap, stock 302 casting late model heads, edelbrock performer dualplane intake, and a TQ from a 73 400 manual car. The heads and intake havesmaller ports and valves than my stock J heads and iron intake. Will theswirl port heads still outperform the old J’s with the iron intake? It seemsthe heads might benefit from some light porting in the intake runner nearthe pushrod holes. What’s your thoughts? Also my car will mostly be cruisingaround town and such, maybe a little time at the strip, nothing serious. Ismy cam too much? It seems like a lot of overlap. I’m still in assembly so itwould be easy to change it.



If you don’t wanna go Magnum, I’d sure MUCH rather have 308s. What you arebuilding is gonna be down 25-30HP at a minimum. 302s are nice for a 273, orvery mild 318, build.

With the 4-speed, the cam will be a bit lumpy but will make some real HP (ifyou get heads that flow). If you stay with the wimpy heads, then, yes,downsize the cam a bit.


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