[PonchoMike]

Getting ready to order a set of roller tip rockers for the GTO. Got a couple of questions before I do though.

1. Should I order a kit with new pushrods or just reuse the stock ones?

2. Will 1.65's work with the stock valve covers, or should I just stay with the 1.52's?

Running a 389, tripower.

[jarhead]

Before you order the pushrods determine what length you need. Comp Cam doesn't differentiate between early and late head geometry. The pushrod length they include in their kits may work fine for 400 and maybe even late 389 but the ones they included in a complete kit that I bought ended up being 1/2 inch too long. This caused extreme wear on the valve guides and beat the heck out of the top of the spring retainers. The length should have been 8.6 - 8.7 instead of the 9.1's in the kit. Measure before you buy. The roller tip should run across the tip of the valve during full travel.

[PonchoMike]

Ordered them separately from the rockers. Used the p/n that they have listed on the Comp Cams website, #7851-16 for 55-79 350-455's and just gave that number to my local shop so they could order them. Wonder if I call Comp Cams if they can give me the length?


Called, one's I ordered are 9.136 in length. Informed me that was the the orig specs. Guess I need to find out what the length is for a 65 389 pushrod. Anybody know?

[FFD]

I'm far from an expert 9.136 is the stock length I think. http://carcraft.com/techarticles/116...ush/index.html is a short read on setting up length usually comes out shorter

[jarhead]

For what it's worth, the ones you bought are the same ones that I had the problem with. According to "Pontiac Heavy-Duty Parts and Specs" by Craig Hendrickson and Kern Osterstock the length for 61-67, all V8 is 8.715. 1967 GTO and 68-79 all V8 is 9.145, Again I urge you to have the machinist measure for the correct length before you order. Here's a picture of what happened to mine.

[TRKN]

Jarhead is right, you really have to measure and check the pushrod length. You also have to consider the fact that most heads have been milled and blocks decked, thus shortening the distance between the rocker and the lifter.The other problem I've seen arise is the different lenght valves used when a unknowing machine shop replaces the valves, or the valve seats are sunken from excessive wear or machining. Buy the adjustable push rod from comp and use that to determine the correct lenght. Then order the correct push rods you need. Don't skip this important step, you'll be sorry! Good Luck! J.

[PonchoMike]

Well, got the rockers installed finally and the car's running. Thought I'd pass along some info though, might help somebody down the road a ways.

ARP studs had ben installed, which is good, but caused some headaches when I was installing the rockers. The ARP studs must be a little too long for the use of polylocks, without using two washers as spacers between the rocker ball and the lock. One spacer won't work, gotta use two in order to be able to use the locks. Should have realized this when I took everything apart and saw that two had been used. Thought with the ball being a little taller though that I could eliminate one of the washers. Wrong. Ended up taking everything apart and using the second washer. Runs nice now, seems to pull a little harder through the gears. Idling just a bit rough, might try backing off on the adjusments just a tad and see if it smooths out. BTW, new stock length pushrods were used, 8. something inches in length, and I reused the polylocks that were in use with the stock rockers. Of course I picked the hottest week of the summer to do the changeover which didnt help matters either.

[jarhead]

Glad it worked for you. Seems 8. something is the correct length for your application also.

[PonchoMike]

Made sure that I checked the length of the old ones against the new ones.