clevoxt

Hi guys this is my first post on this excellent forum.
Im currently changing cams and need some advice on a intake combo.I have a dual plane and a single plane manifold,a 600 vac sec and a 780 vac sec holley to choose from.Im after strong low to midrange power,fuel economy is not important.
351 clevo
crane cam 218/218 524 lift
crane valve springs and moly retainers
Tri-y extractors and twin 21/2 system
c10 auto
3.50 gears

Also i have a block that has slight cutouts at the top of each cylinder,2 each cylinder.I know that my current block does not have them.The block is out of a std 302 xa sedan.

cedric

also seen block with these cut-outs was told they were machined for valve clearance. not from factory. didn't think valves would go anywhere near there

clevoxt

Yeah its strange cause its a dead stock 302 block out of an xa falcon 500 with matching numbers.The block has jh on it so its a brisbane supplied block,but i also have a brissy 351 block that dosent have them.Check out pic,there're circled in black.

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russxr67

clevoxt,my opinion is that you don,t have enough "motor" to warrant the change to a single plne or even a larger carb at the power level you will make with the parts you have.I think a 600 vac sec is a great all round performance carb and ideally suits the dual plane in question. If ,at a later stage you up the ante and install more cam,comp etc then the single plane and larger holley would be the go for that particular application.
Your combo should make good power in your rev range that you are after and to boot your economy should be reasonable as well.

brenx

Agreed, a stock manifold or edelbrock duel plane if you after saving weight should be all it'd need.

Brenden

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davis

...these are commonly found on engines with 4V "large valve" heads in the US.

The cut-outs are not for valve "clearance" but for unshrouding the valves, gaining better low-lift flow. Of course, considering factory "tolerances," it is likely that they needed them for clearance, too!

:davis:

clevoxt

So is this a rare block for a 302,as it had the std 2v closedchamber heads on it.

jg66me

I dont think this is rare. Most blocks I have had this feature, both 351 and 302.

Steven B

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xbgs351

Notches are not rare.

STROKEXD

I've never seen one without the notches myself..

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