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Post Info TOPIC: Swapping my Big block heads over


Poncho Master!

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Posts: 1667
Date:
Swapping my Big block heads over


hey hey!

for the big block peeps, I am changing my heads. Tight budget and want to get a little more bang. presently running 781 heads in standard form. Good heads with hardened seats. Also have a pair of 049 heads spare on the shelf, also good heads but not hardened seats standard form. Both type heads are decent heads, preferred heads for a street car and for performance. Both 781 and 049 are oval port, open chamber.

have picked up a pair of very very low milage heads from a 502. Intake runners same size, exhaust outlets slightly smaller, but not by much.

But, also has larger valves and are closed chamber heads. Hoping to get a little bit of a gain over the existing heads.

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cutting a roof off a four door is NOT a convertible.....

65 Parisienne convertible.one of 49 built for RHD export market,402BBC, T400, 2500 stally, posi rear, upgraded brakes with front discs, FUEL FAST efi custom built by me.



Canadian Poncho Superstar!

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Posts: 6804
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How much of an increase in compression ratio are you expecting with the closed chamber heads?

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70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 



Poncho Master!

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Posts: 1667
Date:

seventy2plus2 wrote:

How much of an increase in compression ratio are you expecting with the closed chamber heads?


 Not sure, havent had the opportunity to figure it out yet.



__________________

cutting a roof off a four door is NOT a convertible.....

65 Parisienne convertible.one of 49 built for RHD export market,402BBC, T400, 2500 stally, posi rear, upgraded brakes with front discs, FUEL FAST efi custom built by me.



Poncho Master!

Status: Offline
Posts: 1667
Date:

Little update on my head changover. The pistons hit. Put one on to test and rotated the engine, piston hit so back to my other heads. Had to get all of my stud therads in the block recoiled. Now have 7/16 studs and a nice set of roller rockers. Also updated my fast EFI to sportsman so now program using a laptop, not so self learn.



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cutting a roof off a four door is NOT a convertible.....

65 Parisienne convertible.one of 49 built for RHD export market,402BBC, T400, 2500 stally, posi rear, upgraded brakes with front discs, FUEL FAST efi custom built by me.

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