1965 426 wedge

Coleydog · 09-30-2023, 09:37 PM

A question for you guys, the NHRA specks for the 426 wedge is max bore of 4.33, the standard bore on a 440 is 4.32. NHRA shows the pistons allowed for the 426 but Im wondering if I can use a 440 block and the standard bore piston with NHRA excepted numbers. I hope I explained this right. Maybe call the tech people but I have no phone number. Thanks

GTX JOHN · 10-01-2023, 12:56 AM

I do not see why you could not run the 440 block but
it will be difficult to find one that would clean up at .010
over. They all have pretty worn cylinder bores
that I can find any more

Back in the day you could buy from Mopar Perf. an unbored
440 block that could be built at .060 over for a 426. But I have
not seen one for 30 years.

Coleydog · 10-01-2023, 02:38 AM

I have a 70 and 74 block with good cylinders so that’s not a problem. I’m thinking more about the piston numbers

Steve Stasko · 10-01-2023, 10:04 AM

I don’t think it would be an issue in SS, but it’s probably a no-go in Stock as the 426W and the 440 have different compression height on the pistons. Ultimately NHRA tech would make that call.

Kirk Morgan · 10-01-2023, 11:18 AM

You can use the 440 block with a approved 426 piston as long as you are not .080 or more on the 426 bore and the block has the same deck height as specified for the 426 block.

Coleydog · 10-01-2023, 08:46 PM

Just looked at both specs 426 has a 2.015 comp height .042 deck with a .020 gasket. 440 has 1.94 ch .027 deck and a .021 gasket. No 440 piston has that ch except the 6 pac but it has valve pockets, a no no. So it’d have to be a .070 over 426 piston with the right numbers on top. What a can of worms.

09-30-2023, 09:37 PM	#1
Coleydog Senior Member Join Date: Jul 2014 Posts: 572 Likes: 39 Liked 53 Times in 38 Posts	1965 426 wedge A question for you guys, the NHRA specks for the 426 wedge is max bore of 4.33, the standard bore on a 440 is 4.32. NHRA shows the pistons allowed for the 426 but Im wondering if I can use a 440 block and the standard bore piston with NHRA excepted numbers. I hope I explained this right. Maybe call the tech people but I have no phone number. Thanks

10-01-2023, 12:56 AM	#2
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,733 Likes: 2,802 Liked 2,486 Times in 697 Posts	Re: 1965 426 wedge I do not see why you could not run the 440 block but it will be difficult to find one that would clean up at .010 over. They all have pretty worn cylinder bores that I can find any more Back in the day you could buy from Mopar Perf. an unbored 440 block that could be built at .060 over for a 426. But I have not seen one for 30 years. __________________ John Irving 741 Stock 741 Super Stock

10-01-2023, 02:38 AM	#3
Coleydog Senior Member Join Date: Jul 2014 Posts: 572 Likes: 39 Liked 53 Times in 38 Posts	Re: 1965 426 wedge I have a 70 and 74 block with good cylinders so that’s not a problem. I’m thinking more about the piston numbers

10-01-2023, 10:04 AM	#4
Steve Stasko Member Join Date: Jul 2011 Location: Western PA Posts: 455 Likes: 13 Liked 274 Times in 143 Posts	Re: 1965 426 wedge I don’t think it would be an issue in SS, but it’s probably a no-go in Stock as the 426W and the 440 have different compression height on the pistons. Ultimately NHRA tech would make that call.

10-01-2023, 11:18 AM	#5
Kirk Morgan Member Join Date: Jan 2009 Posts: 230 Likes: 1 Liked 80 Times in 44 Posts	Re: 1965 426 wedge You can use the 440 block with a approved 426 piston as long as you are not .080 or more on the 426 bore and the block has the same deck height as specified for the 426 block.

10-01-2023, 08:46 PM	#6
Coleydog Senior Member Join Date: Jul 2014 Posts: 572 Likes: 39 Liked 53 Times in 38 Posts	Re: 1965 426 wedge Just looked at both specs 426 has a 2.015 comp height .042 deck with a .020 gasket. 440 has 1.94 ch .027 deck and a .021 gasket. No 440 piston has that ch except the 6 pac but it has valve pockets, a no no. So it’d have to be a .070 over 426 piston with the right numbers on top. What a can of worms.