I have an 87 IROC 350 with TPI and a factory roller cam, I purchased a set of GM heads # 10125377 and would like to know if the valve springs on these heads will work with the roller lifters, cam, The springs are # 3901068 which are 80# @1.70"
Thanks !!

 

That's not even a valid part number. I just tried GM directly. Please tell me you goofed up and gave us the casting number. If so, all you should type is 377 heads. And why give us the number instead of just telling us which heads?

 

That is the GM number on the box, They are old stock, I can't find out what valve springs my 083 heads have for springs to compare. The casting number is 14096217, The casting number on my engine is 14101083.

Thanks

 

Never trust mystery cams or mystery springs. Either test them to find their specs, or replace them with known parts. Your local machine shop can help you determine the rest of the specs on your springs. 80 pounds on the seat is rather low for a hydraulic roller, but is probably fine to 5100 rpm if you have 1.94" valves. If 2.02", then less rpm, due to the 2.02s being heavier. It may not seem like much to humans, but at 5000 rpm, it makes a real difference. 80 pounds on the seat is typical of the LM7 / LR4, but those have 1.89" valves with 8mm stems, and tiny retainers. 80 pounds on the seat is also typical of a stock setup for a hydraulic non-roller SBC.

 

Thanks, I was hoping the springs would work, I will have them tested. If you go to gmpartsdirect.com and find small block heads the 10125377 a picture and specs.

Thanks.

 

Any idea what roller cam came in the stock IROC 87 350 ?

 

I tried that too. nothing.
The '87 TPI 350 cam has about .404/.415 lift with 1.5:1 rockers. It's really mild, those springs should be fine if they have over 200 pounds at 1.3". If they have less, spend $30 on a new set of 98111s from www.competitionproducts.com. these will take near 0.500" of lift, so they're okay if you want to change cam or rockers.