302 heads-Is it worth putting them on a stock 318
The 2 reasons these heads have ANY kind of following are:
1. For decades Mopar employed that huge and ugly open combustion chamber in both SB's & BB's for the vast majority of production years. Mopar guys seeing and hearing the Chevy and Ford camps raving about their closed chamber heads and extolling their virtues lead the Mopar camp to seek out closed chamber offerings made by Mopar. Many of us Mopar guys were now believing that a closed chamber head was superior for (compression or flow or whatever) and sought them out.
2. HotRod published a magazine article written by no other than Steve Dulcich titled " Junkyard Jewel" that featured a bucks down 318 build that even I salivated over at the time 'cuz I had zero dollars and no real skills or experience. The junkyard jewel featured some magnificently ported '302 heads and the engine made I think a hair over 401 HP which at the time was pretty formidable. In one of our face to face meetings I asked him about that build and he smiled and told me that Bryce had ported them and pushed the S.S. so hard to get flow they didn't make it off the dyno. At the time Steve even expressed a little remorse that he had been responsible for the '302 following as they are extremely poor performing and aren't worth the time to get them to perform---unless your time is worth nothing.
Still years later I had the chance to play with a set on a personal project. They flowed an absolutely abysmal 153 cfm @ peak .430" lift AFTER installing a 8mm stem 1.92" Magnum valve. Still I used them on a 347 "stroker" 318/360 crank which I documented here on FABO. I tested it on the dyno and it was probably one of the worst engines I've ever built at least according to the dyno. I think it made about 350hp/350tq. I don't remember exactly but it was lame. In my mind it should have been
+30 at least. Anyways never again...I see a set of 302's and I'm tossing em back in the furnace for remelting into something more useful. J.Rob
Finally someone educated confirms my unqualified suspicion.
I played withso many 318's when I couldn't even afford a cheap gasket set that I lost count.
I always thought the 302 heads were too restrictive to be good despite the compression bump,and my amateur porting couldn't compensate.
My personal experience with these was using them on a bone stock late 70's 318 with pistons so far down in the hole I was shocked.
Even with the fresh valve job there was zero noticeable improvement.
Likewise the roller engine I pulled these off of had flat tops as close to the deck as I have ever seen on a 318.
This got a set of small valve j heads and a used racer brown flat tappet cam.
When the throttle stuck and I missed a shift the valves hit the pistons at 7200 rpm.
This was hardly an apples to apples comparison but one engine struggled to breathe by 5000 and I'd the other would have had good valve springs who knows how high it would have turned.
I grew up in an old school shop that was well regarded for Mopar stuff.
Many 318s went out the door with 360 heads milled .030,stock replacement 340 valve springs and a crane fireball cam.
I don't see the hype on these heads for performance.
Maybe fuel mileage.