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-   -   Chevy 302 Buildup--Needing some advice! (http://www.hotrodders.com/forum/chevy-302-buildup-needing-some-advice-35322.html)

Jeremy McGlade 03-03-2004 03:31 PM

Chevy 302 Buildup--Needing some advice!
 
Hey, guys. I'm trying to build a 302 with a 67 small journal 327 and a steel 283 crank. I researched quite a bit, and I bought parts, but one important piece is going to cost quite a bit more than I had anticipated. The 5.940" L99 PM connecting rods that have been mentioned by others, they used to be 250 a set from GM performance. They discontinued them as a complete set, and to buy 8 of them individually would cost more than 700 dollars (a bit more than I want to spend). I already have the rod spacer bearings, 327 hyper flattop pistons .030 over, the block, and the crank. Are there any other rods that would bring my 1.675 comp. height pistons high enough in the hole? I don't want to go with the 5.7 rods, as the 1.785 comp height pistons (original 302) cost a mint as well, and are too high compression. I also liked the idea of a 1.98 r/s ratio in a high winding motor.

I was wondering if anyone could still source me a set of the L99 PM rods as a complete set a little less expensive than buying them individually? I've checked around to see if anyone had a set in a warehouse, but to no avail. Also, is it possible to use the 5.850" rods and deck .1 off the block? That's a helluva deck job, and I don't know if it's possible, but that would give me a 1.95 r/s ratio. Would a 327 block be able to handle that? That may be a better option if I could find some small journal 5.850" rods because then I wouldn't have to use spacer rod bearings. Any help or advice you guys can give me would be greatly appreciated. And for you guys who are asking "Why a 302?" I ask you Why Not? If I see another "baddest engine in town!" 383 stoker, I think I'll puke blood.

Thanx in advance,

--Jeremy

Cstraub 03-03-2004 03:57 PM

How are you figuring your compression height?

Chris

Jeremy McGlade 03-03-2004 04:31 PM

Those are stock figures from various piston manufacturers. The stock 327 piston is 1.675, 302 was 1.785, and a 350 with 5.7" rods is like 1.561 I think.

Sandflea427SS 03-03-2004 04:35 PM

Jeez...Jere....ride ebay like a hot young lady of the evening...
I have bought many a 5.7 powdered rod off of ebay for $40. I have seen the L99 rod sets for around $80-90. PM and I'll get you the site of a core company in Connecticut! (when I have time)

I thought about doing a low compression 383 turbo motor with the L99 rods and flat top 383 pistons!

rock on you high winding mo fo!!!!!!!


"how about building a 383,.....yeeps!!!!
::

Cstraub 03-03-2004 04:45 PM

Okay, to figure compression height:

Stroke/2= sum + rod length= sum - deck height.

3"/2 = 1.5" + 6" = 7.50" - 9.020 = 1.570" CH


I'd use a 6" rod and 350 chevy piston.

jimfulco 03-04-2004 12:35 AM

Might try to email kay454 at Ebaymotors. He was parting out some L99 motors a couple of months ago.

Jeremy McGlade 03-04-2004 06:08 PM

Man, I wish the 6" rod setup would work. Unfortunately, however, 9.020-7.5=1.52. Thanx for the formula, though, I made another mistake in getting the stock 327 pistons. With the 5.94" rods, I would need a 1.56 height 350 piston with this combo, not a 1.675 327 piston.

Oh well, the quest continues.

jimfulco 03-05-2004 01:36 AM

You might be able to use the 5.85" rods on this page with one of the thicker head gaskets:
http://www.flatlanderracing.com/crhbeamscat.html

1.5" + 5.85" + 1.675" = 9.025"

Don't know how much they weigh, though.

Cstraub 03-05-2004 08:20 AM

Ooops, I did hit the wrong button. Use a 6.250" rod, that is 1.250" CH.. That is a shelf stock 6" rod piston for a 350.

Chris

machine shop tom 03-05-2004 09:06 AM

Why all the fuss about rods and pistons? Just use a good small journal rod, and normal 302 pistons. Straightforward and practical. No sense in making it more difficult than necessary.

Jeremy McGlade 03-05-2004 08:33 PM

Well, I was trying to get into this inexpensively is the main reason for not going with the stock 302 pistons. The 6.250 rods are a bit pricey still. I had another idea, but this one is real iffy. The Ford 351W has pistons available with a 1.774 deck height. I could use this with the 5.7 rods, but heres the trick. The pin on a ford piston is .9122 whereas a chevy is .9272. Can a good machinist bore the pin over .015? Or are there bushings available to use a Ford pin on a Chevy rod? Has anything like this ever been done? It would obviously take away a bit of the piston strength, but would it still be useable? This would be cheaper than the TRW 302 pistons, and I could still get a compression ratio useable on pump gas, unlike the TRWs which all I've seen are 12:1. If anyone has any experience in boring pins, please let me know.

Thanx again for all your support and bearing with me.

--Jeremy

jimfulco 03-06-2004 01:46 AM

Some of KB's Ford pistons have .927" pins, but I don't think the Ford valve reliefs are suitable for Chevy valve spacing & arrangement (left exhaust/right exhaust, etc.). I wonder if you could use a 6" free-floater rod & have it rebushed a little closer to the big end, & use a "rebuilder" 350 piston with 1.54" height & maybe a thick head gasket. Dang GM just has to ruin everything don't they?

deuce_454 03-06-2004 09:07 AM

Another alternative is to use ford 300. I6 rods and go all out and buy the custom pistons you want. ford rods costs about 25$ each from PAW (PAW can hone them to floating chevy pin diameter for very little money) and are almost 6.2 inches long (I forget exactly) and thet are plenty strong. and since you want to tailor your pistons anyway. just get a set of custom Ross, CP, JE or Wiseco or whatever brand you prefer... and specify for ford pin diameter


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