Tenxal

tenxal

Well Known Member
Al, are there many stock eliminators that run factory OEM aluminum big block Chevy heads like the L 89 motors ?

The aluminum headed 396-375's are one of the most popular upper class Stock Eliminator combos. NHRA allows the use of the GMPP 401 aluminum head and it's a markedly better piece than the originals, especially the exhaust port.
 
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Tooth

Well Known Member
Supporting Member 3
The aluminum headed 396-375's are one of the most popular upper class Stock Eliminator combos. NHRA allows the use of the GMPP 041 aluminum head and it's a markedly better piece than the originals, especially the exhaust port.[/Q
A while back I was looking for some aluminum heads for my street car and I ran across a set of the 3946074's are these castings popular? I was told they came out on ZL1 and L88 427's they are a matched pair are dated 69 I've done a lot of research on them in this is true. I took them to a place called Noland cylinder head in Kansas City. I done some research and seen that they were bad about pulling the exhaust rocker arm studs out. So they put some kind of inserts in to give the threads more purchase for spring pressures. I run them on my Nova now. Thanks for the information and it sounds like you have to be somewhat of a engineer, scientist, NASA nuclear physicist to run this class. Thanks again and keep us posted.
 

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tenxal

Well Known Member
A while back I was looking for some aluminum heads for my street car and I ran across a set of the 3946074's are these castings popular? I was told they came out on ZL1 and L88 427's they are a matched pair are dated 69 I've done a lot of research on them in this is true.

There's probably no BBC head more misunderstood or subject to urban legend than the 074's. Yes, that was the casting number used on the '68-9 L88's and the '69 ZL1's....open chamber, rectangular port. It was also the basic casting used on the '71 LS6- 454-425's that came in very limited numbers in Corvettes and Chevelles.

In reality, there was the first design (squared exhaust ports like the iron 840/291 heads) and the second design with the round exhaust ports. I've seen many sets of Series 1 heads with '69 casting dates but with the Series 2 '71 round exhaust ports. There were thousands of these heads sold over the counter. Plus, the marine market was full of these hybrid heads.

.....it sounds like you have to be somewhat of a engineer, scientist, NASA nuclear physicist to run this class.

Not really. But you do need to keep an open mind and be willing to look at everything, even if it means not following the crowd.
 

tenxal

Well Known Member
Went to the semis at the NHRA Div 5 National Open in Kearney, Nebraska last weekend. As far as performance this season, the car went 11.10 at Earlville, Iowa and 11.12 at Rock Falls, Wisconsin. At Kearney, we have an altitude factor of .20 and it went 11.31, which factors to 11.11.

Now it's time to go to work for next season! :)

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tenxal

Well Known Member
I also crew occasionally on a good pal's Competition Eliminator car. 376 inch splayed valve Chevy, 1,040 h.p., Liberty clutchless 5 spd. Here's a few pics of it.

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The Kia Soul goes in the stacker trailer along with the golf cart.
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After each pass, the data is downloaded and the clutch is serviced. Base pressure, counter weight amount and clearance are all constantly balanced to make sure it has just enough clutch...but not too much. Here, my hands are about to get in the can. This was at Brainerd this season.
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Tooth

Well Known Member
Supporting Member 3
Cool stuff, today somebody was trying to talk me into a Liberty transmission for my 30 Chevy coupe. I would need to change the input shaft to the can size that I would use but it was definitely catching my attention! It even comes with extra gear ratios.
 

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tenxal

Well Known Member
Cool stuff, today somebody was trying to talk me into a Liberty transmission for my 30 Chevy coupe. I would need to change the input shaft to the can size that I would use but it was definitely catching my attention! It even comes with extra gear ratios.

If it's a true clutchless trans, it would be a miserable street transmission. Even the face-plated clutch assisted transmissions are a challenge.

The GForce Street 5 speed would be an excellent choice. It's based on the T5 and they can refit a used T5, as well.
 

Tooth

Well Known Member
Supporting Member 3
Yes sir I'm aware of this, and the 30 Chevy coupe with a 409 will be a race car. I was told that the t101 g-force with a clutch shift or non clutch shift used is around 3 Grand. They recondition them and sell them use from the factory...
Haven't really made a decision yet anyway just checking all the options.
 

wristpin

Well Known Member
Yes sir I'm aware of this, and the 30 Chevy coupe with a 409 will be a race car. I was told that the t101 g-force with a clutch shift or non clutch shift used is around 3 Grand. They recondition them and sell them use from the factory...
Haven't really made a decision yet anyway just checking all the options.
Option 2 is give car to me as X-mas gift.:cloud
 

tenxal

Well Known Member
Everything came apart right after our last race for a freshen up. I'd been keeping a good eye on the camshaft all season as several of the lobes were starting to look pretty herky. The valve lash wasn't changing but toward the end of the season I felt the car was off .05-.07 from where the last dyno numbers were and what the weather records showed it should have run. It also started to not be responsive to changes...a sure sign something limiting the tune up.

The leading/trailing edges of the lobe ramps looked like this on disassembly:

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The 'dwell' style lobes we use on the Stockers are pretty different. Basically, they lift the valve extremely quick and then transition very fast to the top of the lobe where it 'dwells' for quite a while, then slams shut quickly on the closing side. My engine specs are .390 intake and .410 exhaust, so you don't have much to work with, anyway. It takes a fair amount of valve spring pressure to keep the lifter on the lobe and to not loft it as it goes over the opening ramp or have it crash the lobe on the closing side. The result is you have a tremendous amount of pressure being applied to a very small area of the lobe. We dance around with nitriding, cryo, REM polishing, lifter face oiling holes, reading the alignment of dry chicken bones placed by Swedish virgins in the moonlight...but the bottom line is these things just have a life expectancy. No complaints on this one as it had over 200 passes plus dyno sessions on it.

Everything is back from the precision machining wizards at Victory Engines in Marshall, Mn. and going back together. Several days were spent tweaking different oil ring packages to lighten up the drag a skosh more. Sorry...no 'eye candy' in these Stock engines. :dunno Matter of fact, they are downright boring to look at.

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Tooth

Well Known Member
Supporting Member 3
Al, I stopped and talk to Val the other day and he was telling me his machinist would get a little bent :tantrumwhen he asked him to take .002/.003 off the Piston Dome height. But he always did it for him. I talked to him about his days back with his Nova and his Wagon in his superstock days and you could see him glowing and getting out the pictures! Used super stockers are a special group of guys that That Pays particular attention to details and there's certainly nothing wrong with that.. my question to you Al is how do you check your converter slippage and your transmission clutches?
Do you ever put your converter on a dyno to check how tight or loose it is? What is your converter in your transmission cost if you don't mind me asking? And how many passes do you get out of them. what type of lubricant do you use in the differential (rearend)??? Thanks for the updates it is really interesting to me! :good
Did I tell you he gave me some of his block filler?20191104_151853.jpg
 

tenxal

Well Known Member
... my question to you Al is how do you check your converter slippage and your transmission clutches? Do you ever put your converter on a dyno to check how tight or loose it is?

There are some reliable formulas to figure slippage. Honestly, the E.T. slip is the final determining factor on a convertors performance characteristics. In general, you want to come out of low gear no closer than 500-600 rpm above the convertor 'flash' speed to avoid laying back on the convertor. The thing is...some combinations like a little 're-flash' at the 1-2 gear change. ;)

What is your converter in your transmission cost if you don't mind me asking? And how many passes do you get out of them. what type of lubricant do you use in the differential (rearend)??? Thanks for the updates it is really interesting to me! :good Did I tell you he gave me some of his block filler?

A high quality convertor will generally run close to $1,000, depending on options and if you've got some sort of working relationship with the company. I use Dynamic convertors...great company to work with. As to life, they are pretty good. Barring breaking the stator or damaging the unit from an engine blow up, they are very durable.
 

MRHP

 
Supporting Member 1
I just ordered a new 8 inch converter for my altered. They wanted dyno sheets on the motor, weight, tire dia, gear ratio, first gear ratio, altitude, and about twenty other things. Hope it performs as promised. If not they will modify to make me happy. Not cheap by any means, but quality parts are rarely cheap.
 

tenxal

Well Known Member
I just ordered a new 8 inch converter for my altered. They wanted dyno sheets on the motor, weight, tire dia, gear ratio, first gear ratio, altitude, and about twenty other things. Hope it performs as promised. If not they will modify to make me happy. Not cheap by any means, but quality parts are rarely cheap.

Who are you working with for your convertor?

Torque convertors are pretty good little dynos! ;)
 
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