Mike Graham/Gary Summers

[Mike Graham]

What I was saying was that both cars that I am associated with have the DA head. That is the head that is listed in the blueprint spec,so by definition , it is the correct head. The takeaway should be to check the blueprint spec before you build a new combination. That is what you will be held to in teardown.

[Rich Wallin]

Originally Posted by Mike Graham

What I was saying was that both cars that I am associated with have the DA head. That is the head that is listed in the blueprint spec,so by definition , it is the correct head. The takeaway should be to check the blueprint spec before you build a new combination. That is what you will be held to in teardown.

My take on this the part numbers supplied to nhra need to be updated .... in my experience as an engine design engineer the suffix change usually is production tool related not base design / performance driven

[QuickII]

I heard from a reliable source it was for altering the intake casting number, and booster modifications, not the head at all.

[BBF67]

That could explain why an intake and carburator was seen being carried into the tech trailer.

[Floyd Staggs]

Break out the pop corn. This might get good.

[FireSale]

For everyone's info, the "D-" at the end of a Ford casting number is a revision suffix. DA is the original head. When an engineering change is made to the part the last letter of the suffix is moved down the alphabet. DC heads have had two changes made to them. They may cc the same, but something has been changed. I think that when the suffix was changed, the factory published HP rating stayed the same. NHRA decided they could document the HP of the DA head but not the others and edited the guide to recognize only the DA as legal. Very difficult to build a 1977 Ford 302 stocker.


'77 Chevy 305/145 has three head castings listed
'68 Chevy 327/350 has seven.


I have a Root Beer in the 'fridge...

[Mark Yacavone]

Originally Posted by QuickII

I heard from a reliable source it was for altering the intake casting number,

77 is one year only, but shouldn't be hard to find.

Originally Posted by QuickII

booster modifications,

So what?

[Billy Nees]

Originally Posted by QuickII

I heard from a reliable source it was for altering the intake casting number, and booster modifications, not the head at all.

I have been told on numerous occasions by numerous Tech people (including Gracia) that NHRA Tech ONLY checks carb model,throttle bore and venturi size. Period.
If there has been a change in that policy, I'd sure like to know!

[Bob Mulry]

Originally Posted by Billy Nees

I have been told on numerous occasions by numerous Tech people (including Gracia) that NHRA Tech ONLY checks carb model,throttle bore and venturi size. Period.
If there has been a change in that policy, I'd sure like to know!

Billy,

I don't want to get pissy, BUT, so it's OK to polish the secondary bores on a Q-Jet, grind off all of the casting flash, remove he choke plate and machine off the choke horn????

CARBURETOR
Must be correct year, make, and model specified for car’s engine;
fuel or air bleed passages may be resized. Drilling idle holes in
primary
throttle blades permitted. Other modifications prohibited.
Sandblasting, grinding, flash removal, dry film coating, or any
other modification to carburetors prohibited. Replacement
carburetors permitted provided they are same model, type,
throttle bore, and venturi size. Computer carburetors use latest
model non-computer carb for engine application.

Doesn't look like it to me, but on the other hand...….

WTF do I know????

[Hacksaw]

Originally Posted by Billy Nees

I have been told on numerous occasions by numerous Tech people (including Gracia) that NHRA Tech ONLY checks carb model,throttle bore and venturi size. Period.
If there has been a change in that policy, I'd sure like to know!

You may be correct, but don't you think an official should drop the hammer if he sees a funky casting number mod? Of course. They are looking, maybe not checking.