351W Head Size Help...

I need to order a rotating assmby for the 351W. Keith Black Hyper pistons, Scat rods and crank. I for sure want pump gas so want compression around 9.5. Local speed shop says I need to know the cc of my heads to determine the compression for the kit that was recommended. I have stock 351W heads: C90E. I searched the web and came up with 60.4 chamber for that head...? The info the speed shop gave me was this:
58cc = 10.5
64cc = 9.6
70cc = 8.9
Part #1-95250-1 $703.95 crank, rods, KB pistons

Can someone confirm the cc for that head # please?

Any other recommendations would be appreciated too!
Block is .040 over. Stock heads. Comp Cam K35-218-3 Kit. Comp Cam pushrods. Comp Cam roller tip rockers were recommended this weekend. Edelb Performer intake with Edelb 600cfm. Motor is for Model A pickup. Wanting mild street performance. Thanks.

OK I got it.
http://home1.gte.net/res03net/faqs/head.htm
I guess the 58, 64, and 70cc numbers are just guidelines...

 

I can't recall the cc size, but I am running the same heads on my Falcons 289, and they work real good on the street. I also have a fair sized Crower cam, windage tray,headers and all that BS, and pull about 21 MPG on the freeway and it's right around 300HP. I think you will be fine for a good running street driver, especialy in a light little pick-up.

 

John,
Your C90E heads are 60.4cc chambers, used from '69-'74.
Personally, I would'nt use Keith Black pistons for ashtrays, and there is a very good reason for it...and I'll tell you why!
They, Silvolite/KB, place the top ring groove to close to the top of the piston, which then requires for you to place the top ring gap at an extreme gap to keep the ring ends from butting after the piston reaches operating temperature.All this means is your giving up power/seal, and the top ring groove is extremely sensative to breaking under "any" detonation.

Your actual compression ratio will depend on the year of your block.
The '69-'72 block has a deck height of 9.480"
The '73 and up block is 9.503"

Are you changing the Rods and Crank because your Stroking the assembly? ...or?

Let me know, I'll be glad to help you out.
Glenn

 

Thanks for the advice. Is the drawback to the KB pistons a feature of all hypereutectic pistons or just theirs?

My whole build is on the verge of going out the window. I bought the '72 351W from a neighbor buddy as a "good" motor. It is 040 over. The plan was install new rings and bearings. The guy I bought it from is, or maybe WAS the guy who is helping me build it.

When the crank came out it was so damaged the machine shop said it wasn't good enough to be used as a core. I bought a crank kit for $200. Then I spent $500 on a special order non-returnable Comp Cam k-kit from a local speed shop.

Builder said the forged TRW pistons/rods looked good. Then when he started cleaning them up he said a couple pistons are bad and some of the rods are outta round. So now I need new pistons/rods.

So I returned the crank kit so I could get a balanced rotating assembly kit.

He magnafluxed the heads and block and said they are good.
Who knows with the way things are going so far....

But now my friend says if I need new pistons, rods, and crank...chances are the block and heads should have some machine work....but I'm already 040 over.

I may have to beg the speed shop to take back my 351W cam kit and get me a 302 kit and start over with the 302 my buddy has.

I just bought an Edelbrock intake at Pomona yesterday too...

FUCK.

 

[ QUOTE ]
Your C90E heads are 60.4cc chambers, used from '69-'74.

[/ QUOTE ]

I've not seen any C9OE heads used (from the factory) after 1970 (that doesn't mean they weren't). From late '70-74, you'll typically find D0OE/D0OZ heads which have the same size valves, but intake ports are smaller than C9OE heads (try finding the Fel-Pro 1262 (old number) intake gasket for them '69 intake - don't exist anymore). Most of the books list 69-74 as the same, but the 69 heads have larger intake ports. I learned this when I swapped my C9OE heads for D0OE heads years ago...of course the C0OE heads have plenty of meat to port/gasket match

C9OE are best of factory SBF heads...if you're worried about compression, run aluminum heads. You can easily get away with 1/2 point more on your CR w/pump gas. FWIW, 351W 4bbl was 10.7:1 CR (flat top pistons in 4bbl vs dished pistons in 2bbl - no difference in heads).

FYI - 75-77 had smaller ports again & the thermactor port blocking the exhaust. After 77, the heads were same as 302/5.0L & included pedestal rockers, small ports, & small valves.

 

More helpful info...thanks again.

The heads that I have supposedly were never installed on this '72 block. They were bought to replace the ones that were on it when the motor sustained the damage... The builder told me over the phone today the intake valve on the heads are a little over 2 1/16" and the exhaust are about 1 9/16".

If I decide to scrap the 351 build and build a 302 instead I can use the C90E heads on the 302?

 

Damn, those are big intake valves! If my math is correct (and you really should check it! ), that's 2.06 & 1.55 respectively. Stock is 1.84 & 1.54. Personlly, I would not have done that. The SBF heads are pretty restrictive on the exhaust side to begin with - for a street car, I would have probably done 1.6 exhaust & the largest intake I could get 1.94 or 2.02 (not sure if there's enough room for a 2.02 & a 1.6). I don't think you can get the exhaust to flow well enough to truly take advantage of the larger intake valve - the exhaust ports need a LOT of work.

Will they work on a 302? The short answer is, they should. Check the cylinder wall near the intake valve though - you should be OK, but always check with bigger valves.

Another thing to check will be piston clearance. Out of the box 302 pistons were never designed with those valves in mind, so the reliefs may not be large enough & certainly won't be the right radius.

The real question is why would you run a 302 when you've got a 351W? It's only about 1" taller & 1-1/8" wider & doesn't weigh but about 40lbs more & has the added benefit of more cubic inches - there's also a bunch of stroker kits on the market now, so you wouldn't have to make your own like I did way back when...

 

John,
Not all Hypereutectic pistons are created equal.
The Sealed Power / Speed Pro (TRW) designs are superior and engineered correctly.
Here are some options, as long as your machinist can "clean-up" the bores with a quality hone proceedure.

1. Install Sealed Power Hyper pistons #H336CP-40 with ring set # E251K-40. This will give you 9.85-1 compression ratio with your '72 block.

2. Install Speed Pro # L2378F-40 Forged pistons and Ring set #E251K-40. This will give you 9.2-1 compression ratio.

3. Install Speed Pro # LW2601F-40 Lite-Weight Forged pistons with Ring set # R8902-40. This combo will give you 10.4-1 compression ratio.

All of these parts can be purchased "Affordably" from Northern Auto Parts.com, Summit Racing, and P.A.W., personally I buy from Northern, great service, price and folks to work with.
As for engine bearings, get Sealed Power #8-3380CPA for the rods, and #5107M for the mains, #1204M for the cam bearings.
Gaskets: Get Fel Pro/ Sealed Power kit gasket set #260-1028.

Best of Luck!
Glenn