My newly rebuilt 302 is on the dyno today. Broke the cam in for 25 minutes yesterday. Baseline pulls today with Dyno shop carb and ignition. Then will put the original carb and distributor in and see what it does.
IMG_0448.jpg
Stock build? Cant wait to see the numbers..
Still at the Dyno. Made 369.3 HP with the original carb!
I will post all the details of the engine later tonight. But it is basically stock with the exception of using a smaller valve stem diameter LS valves instead of the original valves.
Dyno sheet
image.jpg
Still amazes me that a factory engine loves such high revs!!
Block is .030 over, standard crank, TRW original replacement pistons (heavy! 603 grams)
I machined the domes to remove 1 point of compression so 10:1, rebuilt rods, smaller than original 30:30cam, solid lifter Isky. Stock 186 heads with LS valves and springs (same size valve, smaller slightly longer stem). Howard 1:55 roller rockers. Original distributor with a Pertronix unit. Original list 4053 carb with 72 primary jets and 76 main jets. 6.5 on both power valves. Original style Melling oil pump, 70 psi at 7000 RPM Valvoline VR1 30 weight oil.
91 Octane pump gas. Timing all in at 38 degrees.
Quote from: CantRepeat on March 11, 2026, 06:49:29 PMStill amazes me that a factory engine loves such high revs!!
We spun it to 7500 (terrifying) twice but power drops off at 6800.
https://youtube.com/shorts/Si6D57ZCA3w?si=_qCtph64sCoy0Tca
YouTube video a friend posted for me.
Badshifter - Impressive results on your rebuilt 302. Hearing the engine on the dyno was a treat! Brings back memories of my friend's 1968 Z28. - Mark
Respectable for the 302.
Obviously if you want more power you will need more compression, larger cam and matching valve springs.
It's all whatever you want. Much easier to make horsepower with a big block.
Excellent and that 360 plus a few ponies seems to be quite common for those basically stock rascals. Our 68Z did 362HP at 6700 and it's bone stock except for .030 over and crane blueprint cam purchased in 1984, which has basically same specs as original cam. What I wanted to comment on was when our engine was on dyno I was standing beside it in the enclosed room and when your standing beside that at 6700 rpm, it gives you a whole different experience.
Is that a Z-20 cam? Maybe Z-25?
I'm on vacation in Europe for a few weeks. Will post the Isky cam card upon my return. Solid lifter still, more modern/torque producing grind.