GN1s Install Questions

[pmcgrath]

I recently got a set of 8 bolt GN1s as a gift (family gave them to me to help pick up my spirits during cancer treatment) and I have some questions for when I install them.

- What head bolts do you use ... part number?

- Which head(stock GM?), intake gaskets(stock, FP 1200 or FP MS96033) did you use? Do I need exhaust gaskets?

- How much porting is required on the intake?

- Which pushrods did you use ... the 8.85 ones?

- Are the valve springs that come with them ok to use with stock cam for now. I will be updating to the 206 at rebuild time.

- What torque specs did you use for the heads & intake? Is the sequence the same?

I am bolting to a stock block with stock bottom end right now.

All opinions are appreciated.

Thanks,
Paul.

 

[WarpSpeed]

Let's see, ARP has a bolt set for the GN1s, but I can't remember the #,, Did instructions come with the heads? Most parts suppliers can prolly find the # for the bolts if no one posts it.
I used Felpro 1026 headgaskets, torqued to 85'#, using oil for lube,, and in small increments.
I like the stock steel intake gasket, but I ported the gasket a little(Gasket matched the ports.) Don't use the rubber strips between the intake and block, just a good bead of ultra copper or something. Torque to 45'#(in small increments) , I think that's the stock torque. The intake doesn't need much porting, maybe a little smoothing. Also, round the top of the egr tower, if you feel like,,,,,,, or remove it.
I used felpro 1400 header gaskets. Also, test fit the headers to the heads. There's a "boss" under each port that interfers with some headers.
8.85 push rods.
Valve springs should be fine.

 

[9SECVSIX]

Paul
Sending you a personal e mail.
9secvsix

 

[tazgn]

I TRIED torquing the intake bolts to 45 lbs when I first got my GN1's. MAJOR mistake. The threads will NOT handle 45 lbs like the stock iron heads! I now go to 25 lbs and it works great. That little 45 lbs fiasco started a 5 year series of problems and probably about $10K in repairs (stripped bolt holes, leading to water in the oil, leading to shot bearings, crank, cam, etc. etc.). Pretty much everyone after that happened told me that 45 lbs was WAYYY too much for aluminum heads. Everything else though I agree with. Just wanted to EXPRESS my past experiences with GN1's.

Derrick

 

[pmcgrath]

Thanks guys for the advice. It's all very helpful.

Paul.

 

[GNSCOTT]

torqued mine down to 25ft lbs, and went up to 85 in 10ft lb icriments. With alluminum youwant to go down as evenly as possible. I would call Champion on the rest of your ?'s just to be sure. Don't wanna do that job twice.