Ol' Fart's Firebird Fantasy

[oldskool]

Subject: Stocker cams

Question: I think I have ask this on the site before, but do not remember getting an answer. So, what brand of cam do most of the top Stockers use ?

Bullet is the brand I see mentioned most. They have quite a few lobes listed, and can do custom grinds also.

http://www.bulletcams.com/Masters/Hlobes.htm

I assume that most cam grinders don't fool with Stocker stuff because there are so few Stockers around.

[HandOverFist]

Comp Cams will grind whatever you want.

[Dave Ribeiro]

oldskool,

I have used CC in both my 350 & 400 ci 77-Pontiac firebird ..They have a wide selection of grinds to choose from & very good service...I use Crower dual- valve springs & CC hyd lifters , also use Rhoads lifters at times ... Yes, I run 160 # plus spring pressure & CC mag. pushrods, in a 3850 # bird.You don't need all the good stuff to run 2-3 under the index , you will need a good trans & Convertor , plenty of TNT... A good sealing short-block ,heads & a good Q-jet ? Good Luck, $$$$ - jump in the waters is " Fine "...

[oldskool]

As I mentioned at the beginning of this thread, it's main purpose is to gather good Stocker info, not only for myself, but also to help others like me, who have less experience with Stocker stuff.

The only way I know to get this info is to ask those who have Stocker experience, and to find good online info. So I'll just keep firing the questions as I think of 'em.

Subject: Pistons

Question: (1) I see that for some engines there are several NHRA approved forged pistons. So, even if the stock pistons had press pins, are these approved pistons allowed to have floating pins ?

(2) Are all these pistons required to have the same number, size and depth valve reliefs ?

(3) I see that NHRA sets the min weight for the piston. But the min weight for most Pontiac pins is listed as 90 g. That seems like an awfully light pin, doesn't it ?

(4) Also, several of the rods approved for Pontiacs have .990 BBC pin holes. So does that mean that you can order these approved pistons with either size pins ?

http://www.classracerinfo.com/Engine...px?ENGINE=2048

[Mark Yacavone]

Originally Posted by oldskool

As I mentioned at the beginning of this thread, it's main purpose is to gather good Stocker info, not only for myself, but also to help others like me, who have less experience with Stocker stuff.

The only way I know to get this info is to ask those who have Stocker experience, and to find good online info. So I'll just keep firing the questions as I think of 'em.

Subject: Pistons

Question: (1) I see that for some engines there are several NHRA approved forged pistons. So, even if the stock pistons had press pins, are these approved pistons allowed to have floating pins ?

(2) Are all these pistons required to have the same number, size and depth valve reliefs ?

(3) I see that NHRA sets the min weight for the piston. But the min weight for most Pontiac pins is listed as 90 g. That seems like an awfully light pin, doesn't it ?

(4) Also, several of the rods approved for Pontiacs have .990 BBC pin holes. So does that mean that you can order these approved pistons with either size pins ?

http://www.classracerinfo.com/Engine...px?ENGINE=2048

1 Yes, you can float the pins

2 Yes NHRA approved number

3 Don't argue about it, and don't use a lighter pin than you have to.

4. You can use a .980 pin or LARGER if rod is approved.

[oldskool]

Originally Posted by Dave Ribeiro

oldskool,

I have used CC in both my 350 & 400 ci 77-Pontiac firebird ..They have a wide selection of grinds to choose from & very good service...I use Crower dual- valve springs & CC hyd lifters , also use Rhoads lifters at times ... Yes, I run 160 # plus spring pressure & CC mag. pushrods, in a 3850 # bird.You don't need all the good stuff to run 2-3 under the index , you will need a good trans & Convertor , plenty of TNT... A good sealing short-block ,heads & a good Q-jet ? Good Luck, $$$$ - jump in the waters is " Fine "...

Now that's what I wanted to hear ! Reasonable spring pressure, and Rhoads lifters. That means I can run a reasonable cam with Rhoads lifters, in my 455, and get by with a little less spring pressure than you need with your 350 & 400, because I'll be turning less rpm with the long stroke motor--6000 rpm or maybe even a bit lower. Does this sound reasonable ?

Also, with the 455 and Rhoads lifters, I can get by with less stall, and use the 500 + ft lbs of low end torque. Correct ?

[oldskool]

Originally Posted by Mark Yacavone

1 Yes, you can float the pins

2 Yes NHRA approved number

3 Don't argue about it, and don't use a lighter pin than you have to.

4. You can use a .980 pin or LARGER if rod is approved.

OK, so the optimum set-up would be to use a rod / piston / pin / ring combo which would just barely meet the NHRA min weight--is that correct ?

So, for this 350hp 400, that total weight would be 1458 g.

http://www.classracerinfo.com/Engine...px?ENGINE=2048

But I noticed some more specs on this page I need to ask about.

(1) The comp dist is listed as 1.695. But one of the approved pistons has a comp dist of 1.714. So, does that mean that you can use any comp distance you choose, which will optimize your combo with one of the approved length rods, and the max allowed stroke ?

http://www.summitracing.com/parts/sl...w/make/pontiac

(2) Wouldn't there be an advantage to running one of the BBC rods, because of the smaller big end and larger selection of cheaper pins ? The rod journals and bearings will be smaller, and lighter, with less bearing surface. All this will make the rotating assembly lighter, and should rev a bit quicker. Nothing major. But every little bit helps.

(3) That was for the optimum set-up. But it is also the most expensive. So, that brings up my final piston / rod question. Since the SP(TRW) pistons are MUCH cheaper than the other approved forged pistons, is it possible for a low buck guy to use the cheaper pistons and 6.625 Pontiac rods, and build a shortblock that can run slightly under ? Or to ask it another way, aprox how much quicker would the high dollar shortblock run than the low budget one I described ?

[Dwight Southerland]

1) Compression distance is minimum, not required.
2) Yes.
3) a) Yes. b) Reciprocating assembly optimization might be worth .12, including reduction of bearing size and weight.

[Billy Nees]

Originally Posted by oldskool

(3) That was for the optimum set-up. But it is also the most expensive. So, that brings up my final piston / rod question. Since the SP(TRW) pistons are MUCH cheaper than the other approved forged pistons, is it possible for a low buck guy to use the cheaper pistons and 6.625 Pontiac rods, and build a shortblock that can run slightly under ?

Yes


Or to ask it another way, aprox how much quicker would the high dollar shortblock run than the low budget one I described ?

With a "tow truck" motor? Maybe not as much quicker as you think.

Now can I make a suggestion? Seeing as you apparently have a ton of old parts and no body, either find a body that fits your parts or find a complete car. Especially if you are going to try a combo that no-one else has played with.
Put a basic short block together that won't self destruct and go to the track. A basic trans and converter and maybe not the perfect gear like you would in a Bracket car and see what it does. If it doesn't show you SOMETHING, maybe it's really not a good combo. Maybe you won't like driving a 4000-5000 LB car. If it doesn't work, get rid of the car or combo and, not a lot invested. And you can still be having fun and learning.

[oldskool]

Originally Posted by Billy Nees

Now can I make a suggestion?...Put a basic short block together that won't self destruct and go to the track. A basic trans and converter... and see what it does...Maybe you won't like driving a 4000-5000 LB car. If it doesn't work, get rid of the car or combo and, not a lot invested. And you can still be having fun and learning.

OK, thanks for the advice Mr. Billy. That gives me some ideas and also brings up some questions.

I've already got a 455 with 6x heads in a '68 Bird bracket car. Motor running but car not completed. It has a TH400 with 34 element sprag. No tricks--just basic bracket trans. Has a 9" converter--unknown stall.

My engine guy said the car might get into the high 10's. He's built quite a few Pontiac engines and has a 9 sec GTO now. But I think high 10's are a little optimistic. So, I'm figuring mid 11's.

Haven't weighed the car, but I figure just over 3000lb. So, right now I'm doing all calculations based on this 3000 lb car running 11.50.

(1) I've read that every 100lbs of extra weight will slow you down aprox a tenth. Is this what you have found to be the case ? Or ?

(2) Now, for the part about the 4000lb car. All the bracket cars I drove ran mid 12's. When I made a few passes in my 455 Ventura 2, it was a lot quicker. More G-forces and the shift points came quicker than I was expecting. 7.34 sec(1/8 mile) don't give an old dude much time to shift twice and check the other lane. So, a heavy car that would slow things down a bit would probably be a good idea at this point.

Now, I have a Safari wagon I bought for a future bracket car. Haven't started on it yet. It's not old enuff to run a Pontiac engine in Stock--mid 80's. But, since I already have it, and as you say, I may not like driving the heavy car, I just thought that it might be a good idea to go ahead and put the 455 into the wagon and just see what I can get out of it. If I can't get it to go quick enuff at the aprox weight it would need to be for a '76 wagon, then at least I'd have a Pontiac powered bracket battle wagon. It would be using the stuff I already have, to do the testing with.

So what do you think about that idea ?

(3) Another option I considered is running the 10.90 class with the Bird. I think they run that class at all the division races. If it runs as quick as my engine guy thinks it might, that is a possibility, which might take the least amount of time, work and $. But, it's a heads up class, and you must be able to run 10.90 on race day. I think there are also some safety rules that will be required when going quicker than 11.50.

Any thoughts about that deal ?

That's all my questions for right now. But I thought I'd mention that I was reading about the 10.90 class last night. They were talking about the latest electronic, computerized gizmos they have now that will automatically make the necessary tuning adjustments going down the track, that will produce almost exactly the same ET every pass. They mentioned one guy that dialed the exact same ET all season long, in his bracket car. It seems that if you don't have one of these systems, it is getting harder to win a big money race. They're afraid this could damage the sport and reduce the car count, and even cause some of the smaller tracks to close. But they say there is really no way to solve this problem given the level of tech for bracket cars, at most tracks.

Drag racing has come a long way from how it use to be. Now they got tranny brakes, delay boxes, and God only knows what else. This new technology has taken a lot of the fun out of it, and has made it even more expensive to compete. A little Test & Tune is about all most can afford nowadays.

By the way, the name of my wagon is "Woody". And the name of my '68 is "Early Bird". And here's a couple of more racin plates TJ did.