who runs 13sec to 12.80 in the 1/4
stock 302 vs stock magnum yes magnums better but when a 302 is gasket matched to 360 head and worked by a good machineist like BJR why cant it be possilbe for the 302 to flwo as well as the magnum while rasing compression and only spending around 600 on the heads
but im most likely not going to run the 302s because i can just run the stock 360 heads and kb107s and they would out flow the stock 302s with speed pros
Ok, a good machinist can make stock things do better. But, when you start from better, it takes less work to get equal performance from two things. In the comparison of 302 to Magnums, the 302s simply cannot flow enough air to equal the magnums unless they are reworked. That directly translates into dollars to pay the good machinist. A gasket matched set of 302s, with a performance 5 angle valve job, and properly sized valves and no other work will come close to a set of magnums in pure factory stock form. Now, do the same work to magnums, and you are now beyond what 302s could get even with greater $$ spent. Using just money.. lets say you dont have either set of heads, and both set found are perfect low milage examples not needing guide or seat work. For the 302s: initial cost ($100), disassemble/clean and mag($100), 5 angle competiton valve job ($350), hand gasket match/blend/cleanup/back cut intake valves($150), mill flat($70), new valve springs and seals, reusing locks and retainers and existing sized valves. 302 total is $770 plus parts and tax. That will give you a reliable set of heads ready to bolt on with the smaller heart shape chamber that should flow similar to a Magnum head in stock form. Now for Magnums: initial cost ($150), disassemble/clean/mag ($100), 5 angle competition valve job ($350), same hand blend/gasket match and back cut($150), mill flat ($70). Same thing, new springs and seals, all else reused. Total $770 plus parts. But, the heads will flow conservatively about 25% more air at the same lifts, and the chamber is better, with less shrouding.
The 302s simply cant be made to flow as well as a similarly prepped set of Magnums, without spending more money to get there. Think about a drag race. The 302s start at the starting line. The Magnums have a 330' jump on them at the light. They end at the same point, but the 302s require more work to reach that same goal. And in case you're curious... I have a set of 302s on a 360 I ran a couple years ago in my Swinger that are ported and gasket matched(by me), better valves, trimmed giudes and spring seats, and all Comp valve train parts that cost me $1200, because they needed guides and seats...lol.