6.0 Stick Shift Tahoe (NV4500)
#651
makes children cry
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depends on how aggressive your tune is, i reckon. if you've got enough timing to require 93, then a 1/3pt would be noticeable... but if them heads are simply making up for any dynamic compression lost by the cam (vs stock cam + 317s), i doubt it'd make a heap of difference for an 87/89 friendly tune.
...but i've been wrong a time or two in my life.
...but i've been wrong a time or two in my life.
#652
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It’s making low 20*s in the top end on the high octane table, I pulled 4* out across the board for the low table and it acts fine the few times I put 87 in it just as a test.
Screw it, ill go with the cometics that way the comparison between the heads will be all flow and port velocity no change in CR.
Screw it, ill go with the cometics that way the comparison between the heads will be all flow and port velocity no change in CR.
#655
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Getting the chambers measured on the heads today and might start motor tear down this weekend. I think I'm gonna go ahead and replace the oil pump since it's a mystery and I've had low OP on below 32* startups and after I added the oil cooler I lost 5-10psi on warm idle. Just gonna get an M295 and open it up to see if it could use some light porting or not, clean the oil pan and pickup tube and replace the pickup tube gasket while adding one of those little pickup girdle dudes.
Is it worth doing something with the timing chain? IIRC it's a stock gear and chain with no tensioner.
Is it worth doing something with the timing chain? IIRC it's a stock gear and chain with no tensioner.
#656
10 Second Club
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I hate that your probably right especially if it stays NA. My theory on the 3.42s was that not having to shift to 4th would be a huge benefit in the 1/4. I also didn’t expect to ever put a tire taller than 31” under it. I also thought using first with the 33s would help stretch first out making the 60’ time really good. Id still think the 3.42s would be great for a turbo setup letting it load up and build boost and hold boost longer.
If I ever do 4.10s it will be an H2 gear set and E locker it’s by far the most affordable option.
If I ever do 4.10s it will be an H2 gear set and E locker it’s by far the most affordable option.
Or, change nothing and merely add BOOST. There's more than one way to accomplish the same thing.
#657
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Me personally, leave the 3.42s - install a smaller cam more suited for a 5000+ lb vehicle, mill your 862s if you haven't already and treat them to a really good valve job. When you buy tires next time, get a 31" tall tire instead of 33s. If you're stuck on that cam, installing ported 243s, and keeping 3 42s - put a longer arm in that engine. (4" stroke crankshaft)
Or, change nothing and merely add BOOST. There's more than one way to accomplish the same thing.
Or, change nothing and merely add BOOST. There's more than one way to accomplish the same thing.
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Bluecollar Hotrods (01-30-2022)
#659
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Same lift more duration, but yeah pretty obvious, and that's what I'm hoping to gain with these heads. Which, I just had the chambers checked and they are 63cc which is what I thought after having them milled .010, so with a.041 gasket I will be at 10.4:1CR and .033-.037 quench depending on deck clearance. Might need to get a set of .045s.
Last edited by dantheman1540; 01-27-2022 at 07:58 AM.
#660
100% Redneck
I see you've figured out your quench and gasket thickness.