Hey Everyone,
I'm trying to find stock 30 over pistons for my 1970 350 4bbl w the High comp 6cc dish (cast to keep $ down) All I can find is either w-31 flat tops or the larger dogdish tops for 71-80 low comp???? Trying to keep CR around 9.5/1 and I have the smaller 64cc #6 heads....Any help with this would be really appreciated
Also I'm having my machine shop cut in w-31 valves? good idea?
Thanks in advance
Eric

 

Those pistons aren't much more in forged, you may have to bite the bullet and go that route.

 

You could go with the probe pistons they have valve reliefs which I think are 3cc's. They cost a little more but they are a much better piston than the speed pro. Also check out Egge machine they make many pistons

 

Personally I would use the L2321F30. Under $400. That should give you somewhere around what you are looking for in CR. Good idea on the larger valves also. Would not use the smaller stock ones. Cam it appropriately like the comp cams 268H. Just my $.02

 

Well I finally made some choices.......SP2320 flat top forged pistons w/ moly rings,
Comp cams xe268h cam, comp cams 1441 roller tip rockers and heads cut for w31 valves, double roller timing set and melling high volume oil pump with HD shaft. I'm planning on using my stock intake, Quad carb and exhaust manifolds with dual exhaust. Also using felpro gasket kit.040.....hoping for 9.5/1 comp and 325HP.....also had my TH350 built with B & M shift kit and 2500 stall......3.42 posi rear.....no deck or head milling...running in a 1970 cutlass conv
Any thoughts on this build? Also trying to run on mid grade and get decent fuel economy.....minimal steering wheel shake...LOL!
Thanks for your input
Eric M

 

I'm with cutlassefi on this, never seen #6 heads with 64 cc's.

 

So this isn't correct?


ID/ Use Casting
Code Year(s) CID CCs Number Notes
1 '64 330 385101 Used ROCKER SHAFTS rather than
pairs on PEDESTALS.
2 '65 330 ?????? All V-8s now using PEDESTALS.
3 '66 330 60 389394
4 '67 330 60 394497
5 '68 - '69 350 64 397742 Excellent candidate for use today.
Good flowing, and high compression.
6 '70 350 64 403859 W-31's had larger 2.000 intakes. '69
W-31's?
7 '71 350 64 409147 W-31's had larger [2.000] valves.
7A '72 350 64 409147 The 'A' is a subscript, like ¼"
tall, to lower right of the '7',
like | 7A.
8 '73 - '76 350 79 411929 Smog heads. Have huge bb-sized 79cc
chambers yielding poor compression
ratios without extremes of
compensation.
10 '76, '77? 260? 57 550362
2A '76 - '81 260 554715 Easy way to ID a 260 engine.
3A '77 - '80 350 75 554716 1/2" bolt holes.
4A '77 - '79 403 83 554717 Matches the 4A or 4B block, get it?
Easy way to ID a 403. 1/2" bolt holes.
5A '80 - '84 307 64 3317
'85 also???
6A '85 - ?? 307 67 5844 Non-ECM Canadian cars?
7A '85 - '90 307 67 0142 This 'A', and the others from 2A to
6A, is a large capital letter equal
in size to, and immediately adjacent
to the 7, like | 7A.
D3A 350 3948 Diesel.

 

I'm not sure where you copied this from, looks like older FAQ data, but it isn't correct.

 

#6 heads are typically 69cc. Only the #4 heads are 64cc in stock form.