Looking for suggestions and expert advice: Upgrading my 1970 455 engine to a modern 455 engine

First, the shop should be able to tell what head gasket is on it without pulling a head. You can view it between the head and block. Steel shim looks a lot different than later model composite. You can measure that gap to see how thick it is.

Second, you can give up a slight amount of power by retarding the timing a few degrees. Also, adding octane booster will give you extra headroom.

Keep an ear out and enjoy the car.

 

I really appreciate all of you guys providing advise to me.
I think with today's discussion with the shop owner and the head engine mechanic, I'm just really PO'ed.

Not having my Buick to drive for 2 years is not something I had anticipated.
Plus hearing for the first time, during the wrap-up succession that I should be running at least Octane Booster and better yet, racing gas.
That's not the kind of surprise I was expecting. They said after the tuning and the addition of the MSD ignition system, they had the detonation fully under control, and then they unload all this crap.

I have to believe they are wrong. After the first tune, before the MSD ignition system died in less than a month, the car drove great. I never heard any pinging, even at WOT. I never felt any hesitation or bucking. The only reason I took it back because they installed a defective HD fan clutch that would release. So I had them buy another model from Todd Miller. Then the MSD died and they replaced it. Did another tune and found a vacuum leak coming from the carb that had a casting flaw. Replaced that and rechecked the tune and all was where it should be.
I ran the tune specs to one of the engine builders on this forum and he said the tune specs were right on.

I just have to cool off a bit.
That said, I did tell the shop owner that he should be able to see if the head has a steel head gasket. He took a photo but didn't say anything.
I will ask him to check this item out. Again, thanks to all for hearing me out and helping me too. I'am just so frustrated over this ordeal I can't see straight.
VET (Navy)

 

I agree with all that replied!
Take the car home, park it for the winter or whatever you do, and stew on it for awhile.
11 to 1 is not too much compression for pump premium as long as your timing is set correctly.
I’m at 11.99 in my 350 GS, runs awesome on pump premium with 30 total timing, even at 33 total it was good unless you had it to the floor for a bit on the highway, it would start to rattle.
IF you do have 11 to 1 compression, LEAVE IT!
Compensate with your timing.
Hell, low compression can/will detonate.
My uncle bought a new 1975 Riviera, standard 455, they had 7.6 to 1 compression, THEY would detonate from carbon build up on the piston tops, carbon would start glowing.
Cylinder pressure isn’t the only cause of detonation.

 

The picture attached is a felpro head gasket. You should be able to easily see a metal head gasket. Check your cracking compression, Frank listed his for comparison.



.

 

A cam will solve this issue

 

And pick up power .....42° isn't unheard of with iron heads....nor is light springs...I ran my high school car to 12.42 at 106 with stock heads and that exact timing and curve...full timing was in by 2k rpm. But I had something you dont....a cam

You have too much cyl psi for 93

 

Agree with the above- drive it. Run Sunoco 94. And find a different shop - They are looking to get out of any future issues and have been milking you.

 

No Bars! That is a problem.

 

Vet p.m. sent with picture.

 

Thank you very much, I got the pics. VET

 

That's good, I wish Candid Camera had their secret camera setup there, maybe I could figure out what's going on. LoL

 

Not for me...