Fast Burn

mike70454

New Member
Joined
Dec 24, 2019
Messages
8
Karma
0
Car
camaro
Hello, Can anyone please tell the differences between the early (12464298 ) & the current (19300955 ) GM SB Fast Heads?
 

63Half-ton461

Member
Joined
Nov 18, 2019
Messages
65
Karma
8
Car
1978 Monte Carlo 383 slammed
LS-style beehive-type valve springs, they are blue (part # 12625033) and look pretty frickin snazzy on there, that smaller retainer is 1/2 or 2/3 the weight so GM is touting greater power at higher RPM.

That spring (033) on an LS motor uses a retainer designed for 8mm valves where the FB is a 11/32 valve head so i wonder if they're getting their retainers from comp cams, part # 787's

You lookin at buying a pair or replacing one head ?
 

63Half-ton461

Member
Joined
Nov 18, 2019
Messages
65
Karma
8
Car
1978 Monte Carlo 383 slammed
I think Gm Fast burns are some of the best small block heads ever made, in the aftermarket i would compare them to Dart Pro-1's
I don't knows who's behind GM's cylinder head program but you have to admit they have made some pretty decent stuff on both the small block and LS !
I have a couple sets of the Dart Pro-1's and ironically i did them up 3 years ago with the same valve springs, bee-hives are great because they self dampen, don't need that flat heat producing coil on the inside.
 
Last edited:

63Half-ton461

Member
Joined
Nov 18, 2019
Messages
65
Karma
8
Car
1978 Monte Carlo 383 slammed
You puttim on a motor with a roller or flat tappet cam ?
 

mike70454

New Member
Joined
Dec 24, 2019
Messages
8
Karma
0
Car
camaro
Thank you. Roller; hand building a ZZ6 for NHRA stock eliminator. We run that class (crate motor/stock) up here in Canada. Also, NHRA allows it in their "National Open" races (so far!).
 

63Half-ton461

Member
Joined
Nov 18, 2019
Messages
65
Karma
8
Car
1978 Monte Carlo 383 slammed
That sounds like a lot of fun, In your class do you have run the ZZ6 spec or similar cam ?
 

mike70454

New Member
Joined
Dec 24, 2019
Messages
8
Karma
0
Car
camaro
It has to be built to ZZ6 specs. although they have let us "solid up " the hyd. lifters. There is about 40 legal stock & superstock racers in the series. 8 double races at 4 tracks (incl. NY state) plus a NHRA National Open at Cayuga ON. (There's a couple of SS/A Hemi cars, one COPO & one Dragpack Challenger!). We run off of NHRA indexes; it's a blast!
Check it out on facebook: CANAM Superstock
 

63Half-ton461

Member
Joined
Nov 18, 2019
Messages
65
Karma
8
Car
1978 Monte Carlo 383 slammed
Cool. Ive been wanting to try running roller solids on a hydraulic roller profile in a big block i have, i've had the idea of calculating my valve lash so that when the motor is hot the lash is near zero.
Ive been doing this with my 98 cube shovelhead for years and been getting the max out of the Andrews C grind thats in there, the thing is fast and you can barely hear any top noise !
How are guys typically setting their lash cause you def want to preserve as much of if not all your duration and lift ?
 

mike70454

New Member
Joined
Dec 24, 2019
Messages
8
Karma
0
Car
camaro
I start at .015 & it grows to .020 when hot. Oddly, I noticed with the alum head, I gain clearance when hot. My other stocker (LS6 cast head), does the opposite. Hot at idle is not the same as hot at WOT@7200rpm, so you have to watch it. Some racers, if they are setting the record or running someone heads-up, will tighten it up, but you run the risk of burning a valve.
 

63Half-ton461

Member
Joined
Nov 18, 2019
Messages
65
Karma
8
Car
1978 Monte Carlo 383 slammed
I see, interesting, yeah i'd be the guy chasing the minimum lol. When and if i do it i was gonna try and get down to a couple thou. On the Harley its easy cause you can hear it at the end of pipes when they need a reset, they don't need it to often actually. Krank-on, have a great racing season ....
 

Latest threads

Latest posts

Top