Thread: valve sizes

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Can anyone tell me what intake and exhaust valve sizes were installed in the following casting numbers.
casting # 3931063 oval port closed chamber date code D11-9
casting # 3964290 oval port closed chamber date code H20-9
These heads are virgin rebuildable as removed from running engines. Is there any differences between these heads other than casting number and dates? Purchase of these heads depends on your knowledge of these heads. I have not visually looked at them so I need good info. Thanks

3931063 68-69 396 402 and 427 101cc chambers
3964260 69-70 396 402 427 and 454 101cc chambers
This info is from mortec.com

Both good choices in my book, they will make good power even with stock size valves. And with the small chamber size, even using flat top pistons, your compression ration will be pretty good...maybe 9.3/1 or so depending on some other variables.

Thanks guys I'll probably get some Manley stainless valves for them during the rebuild. I guess they are both the same with no difference in port runner sizes or chamber size. Again thanks.

Yep, basically the same...you could even use one of each if you had to.

Originally posted by 1JohnnyO
Both good choices in my book, they will make good power even with stock size valves. And with the small chamber size, even using flat top pistons, your compression ration will be pretty good...maybe 9.3/1 or so depending on some other variables.

Hi, I have just sent you a e-mail and I forgot to tell you that the engine compression will be 10.1/1 and the intake is a dual plan.

Canso, I didnt get an email from you...did you send it thru this forum? What address did you use? John

Originally posted by 1JohnnyO
Canso, I didnt get an email from you...did you send it thru this forum? What address did you use? John

Sorry I'm new at those e-mails...... I decided to send it to you this way instead. So would you please give me an Idea the area of HP I'm in with my Big Block Chev Engine thanks.


Engine; 454 bore out .60 .300 dome piston

Compression; 10.1 to 1

Heads (World Merlin 269cc oval port intake); open chamber 119 cc/ intake valve 2.300 / Exhaust valve1.88 Roller Rockers/ guide plates 1.7
Fel - pro head gasket

Rods; original rods with ARP bolts.

Carb; Holley 850 double pump

Ignition Pertronix flame-thrower billet distributor, Pertronix ignition box and rev limiter, Pertronix Coil 45,000 volts

Taylor wire 10.44 mm

Intake; Edelbrock, Performer RPM Manifolds and Cam Kits (1,500 -6.500 RPM)

Headers; Long tubes 2 inch Hooker super comp. Fenderwell.

Cam; Edelbrock. 560 lift intake.573 lift exhausts. 240 dur.int., .50 246 degree exhausts.

Crank shaft: scat forged.

I have a 66 Canso (CHEVY II) that weight about 2300 pounds with a t.h. 400 transmission with shift kit and a 2800 stall t.q. and 4.10 rear end.

I hope I have no problem getting 500 HP out of this engine!
Thanks! Canso.

Canso, still no email...I just checked my email in my profile, and it's correct...are you just checking on the box for my email at the bottom of my post? I should get it, Im getting email from others here? Anyhow, I just sent you a private message. Thanks, John