L-72, final assembly

shor · #1 08-23-2002, 01:38 AM

L72 MN fa

**Stefano** · #2 08-23-2002, 04:10 AM

Will your Daytona Douglass Yenko make the reunion?

shor · #3 08-23-2002, 01:03 PM

I will make it. The car is 50/50. If it is not ready by then, I will just have to pal around with you and your white one all weekend [img]/ubbthreads/images/icons/smile.gif[/img]

COPO PETE · #4 08-23-2002, 03:41 PM

Man, those pistons look sweet. I should have used them instead of TRW's! Will this motor be a true 11:1 with them???
Peter

Chevy454 · #5 08-23-2002, 03:48 PM

That's what I was thinking, Pete [img]/ubbthreads/images/icons/frown.gif[/img] . I will NOT buy TRW's again.

**Stefano** · #6 08-23-2002, 04:00 PM

Shor,
The pistons look very high in the non decked block. Did the machinist achieve this with the out of the box pistons or was the wrist pin location custom ordered?

Chevy454 · #7 08-23-2002, 04:31 PM

FYI:

The TRW pistons in our last L-72 measured ~28cc, where as they are supposed to be 34cc. I sure wish I had gone with Ross or JE like I had originally planned...oh well, when I build the original L-72 to AMA specs it should be a REAL animal then. If my memory serves me correctly, Pete's pistons were on the "smallish" side as well...Pete?

**Stefano** · #8 08-23-2002, 05:31 PM

That is a big difference, approx. 1/2 point of compression ratio right out the window.

What would you say that would equate to HP wise, about 10-15 at the rear wheels?

shor · #9 08-23-2002, 09:07 PM

Hey guys. We went with the stock NHRA JE pistons 138814 .005 It was supposed to be 4 weeks for the custom order, but was really closer to 8 weeks. The journals on the crank were practically new std/std and we were able to track down a set of new gm 400 bearings.(and an original timing chain and ...ughh nylon gear) The machinist thought I was nuts, but I now have him on my "original" wavelength. He did insist on ARP fasteners though. Yea, it will be an 11:1 compression ratio, at least until I get tired of heading down to Sunoco at the Marina and paying 5.80 a gallon for the purple racing fuel. Nick did say that the advertised factory compression ratios of the day were actually the maximum and a "real" number was always slightly less, like a 10.7 or a 10.8 or 10.9, due to manufacturing tolerences and deviations. He said in my undecked block the top of the piston, the piston, not the dome, will be .030 below the deck at TDC. He said, after examining these JE pistons, that they had the true dome, faithfull in all respects to the original engineering spec. of the day; unlike some other "brands". This with the cleaning and balancing and polishing of the rods should put me at a true 10.7,10.8.( I think that is what he said...does it make sense?) If it becomes too much of a pain, I have a set of 71 ls6 heads waiting on the shelf. I'll keep you posted!

COPO PETE · #10 08-23-2002, 09:30 PM

You are correct Rob. My 12:1 TRW's for the ZL-1 actually worked out to 10.8:1 [img]/ubbthreads/images/icons/frown.gif[/img] Live and learn!!!!) Part of the problem was my deck hieght. I did'nt want to deck a new block. Suppose to be 8 thou. out of the hole , and was 30 thou in the hole! Next time It will have a true 12:1 and then LOOK OUT!!!!
Peter

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