I want to have my heads decked before they go on the car...
Should it be 10 thousandths? How much will this affect compression/will it slightly boost power?
I want to have my heads decked before they go on the car...
Should it be 10 thousandths? How much will this affect compression/will it slightly boost power?
1991 Jewel Green Ford Mustang LX ~ 5.0L / 5-Speed
2011 Torch Red Ford Ranger ~ 2.3L / 5-Speed
1971 White Chevrolet Chevelle Malibu w/ Blue Stripes ~ 8.2L(502) / 4-Speed
Be prepared to check pushrod geometry and perhaps buy new pushrods if you are running E7's which are pedestal mount. For the small increase it'd net versus the money it'd end up costing, I'd leave them alone unless they absolutely need it.
-Paul
1995 GT 'vert
Best times on old 302 combo:
12.03 at 112.5mph NA
Best time with 9:1 compression NA dart block 331 setup:
11.50 at 121mph
Dyno'd: 415rwhp/410rwtq
2004 Z16 commemorative edition Z06
100% stock: 11.9 at 118mph
What are the chances that the heads won't seat right? I'm not interested in performance rather a good seal.
I've got brand new Comp Cams 1.6 rockers and pushrods as well as Trickflow lifters, btw.
1991 Jewel Green Ford Mustang LX ~ 5.0L / 5-Speed
2011 Torch Red Ford Ranger ~ 2.3L / 5-Speed
1971 White Chevrolet Chevelle Malibu w/ Blue Stripes ~ 8.2L(502) / 4-Speed
It all depends if they are warped or not. Its not a bad idea to check them, however if they need milled your new pushrods may not work. Pushrods are always the last thing to buy when assembling an engine as you can not determine their length until everything is together. Deck height, gasket thickness, cam base circle, lifters, etc all have an effect on pushrod length. You may get lucky and be OK with what you have, but if you don't check it you are asking for trouble. Check the swept area on top of the valve and the location of the roller tip on the valve. The roller tip should be centered or slightly to the intake side of the valve at zero lash and the swept area should be kept to a minimum on the valve tip face. Check this with a light amount of grease on the valve tip, setup the rocker assembly gently, and then rotate the engine until the valve opens and closes fully. Pull the rocker off and look at the top of the valve to see where your swept area is and how much travel it has across the valve tip. Also, with stock pedestal mount heads make sure once the lifter is on the cam base circle and you reach zero lash that your torque wrench clicks off between 1/2 to 3/4 of a turn when set to around 20ftlbs of torque. If it clicks off earlier your pushrods are too short, if it takes more than 3/4 of a turn your pushrods are too long. There are shims available to raise the rocker pedestal off of the head which can help with small adjustments if the rockers are too long, but they are for "fine tuning" only. If the rods are too short you will be buying new pushrods without a doubt. Typically milling of the head will make the pushrods too long, and the shims may be all you need depending on how much needs removed.
-Paul
1995 GT 'vert
Best times on old 302 combo:
12.03 at 112.5mph NA
Best time with 9:1 compression NA dart block 331 setup:
11.50 at 121mph
Dyno'd: 415rwhp/410rwtq
2004 Z16 commemorative edition Z06
100% stock: 11.9 at 118mph
I would suggest Brockers on 51 by Century III Mall. Don't know if I spelled that right or not.
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