Identifiying 4V heads

[dbdragracing]

I have a 1970 Mach 1 with the 351C-4V from the factory. I know the eninge is a Cleveland, but how do I make sure the heads are 4V ? I havent removed the valve covers yet. Thanks.

 

[dodgestang]

Look on the upper left hand corner...they will have a 4 cast into them if they are 4v...will be visible with the valves still in place

 

[izzy jr]

Look on the upper left hand corner...they will have a 4 cast into them if they are 4v...will be visible with the valves still in place

would heads from a 70 model 351w have the same markings or is there a diff in 2v/4v heads for the windsor?

 

[RogerC62]

would heads from a 70 model 351w have the same markings or is there a diff in 2v/4v heads for the windsor?

Windsors don't have the same markings. Not sure if there is any difference between 2V & 4V windsor heads, maybe valve size?

 

[D.Hearne]

The 2V/4V Windsor heads for 69/70 used the same castings for each.

 

[dbdragracing]

Thanks for the help...I will look Friday. Later.

 

[nugget68]

The 2V/4V Windsor heads for 69/70 used the same castings for each.

is there a difference in 2v and 4v windsor heads for 68?

 

[D.Hearne]

is there a difference in 2v and 4v windsor heads for 68?

Well there wasn't a 68 351W. But there was a 2 bbl & 4 bbl 302. And yea, they did have different heads. The 4 bbl head was essentially the older C6OE 289 head with a new casting number. (C8OE-F) also these have 4V cast in the rocker valley) Same ports and valves as the 2 bbl heads, but they have the small 54 cc chambers of the older 289 heads. The difference resulted in a higher compression ratio for the 4 bbl motor. (10.5 to 1)

 

[izzy jr]

The 2V/4V Windsor heads for 69/70 used the same castings for each.

Does that mean you could run both carb combos on these heads then a 2v or 4v on the same heads? Just curious since my car has a 68 302 with 70 351w heads and a 2v carb currently that needs rebuilt.

 

[D.Hearne]

Yea, they're completely interchangeable. The 69-74 Windsor heads have slightly larger valves and ports than the 302 heads had. This doesn't affect the carb you're using in this case. 2V/4V is an abreviation for Two Venturi - Four Venturi. A 2 bbl carb has 2 Venturis, that's the narrowest point in the carb throat.

 

[izzy jr]

Yea, they're completely interchangeable. The 69-74 Windsor heads have slightly larger valves and ports than the 302 heads had. This doesn't affect the carb you're using in this case. 2V/4V is an abreviation for Two Venturi - Four Venturi. A 2 bbl carb has 2 Venturis, that's the narrowest point in the carb throat.

So all I would have to do is get an intake for a 4v carb and everything should just bolt on then? So I would need an intake for a 351w right.

 

[D.Hearne]

No, you'd use a 289/302 intake. You've got a 302 block. The 351W's block is taller by 1.3", moving the heads farther apart than when they're on a 289/302 block.

 

[izzy jr]

No, you'd use a 289/302 intake. You've got a 302 block. The 351W's block is taller by 1.3", moving the heads farther apart than when they're on a 289/302 block.

Thanks for the clarification. That's what I was thinking but was not 100% sure about it. What kinda gains would I get If I switch from the 2v to a 4v carb/intake combo?

 

[D.Hearne]

Just off hand---------20-30 hp.

 

[izzy jr]

Just off hand---------20-30 hp.

Thanks, I quess I have yet another item to put on my wish list of things to upgrade/swap out.

 

[D.Hearne]

Thanks, I quess I have yet another item to put on my wish list of things to upgrade/swap out.

Now there IS a 2 bbl you can bolt on that'll give you the same gains. I've used this carb on 4 different engines and it's a great bang for the buck. The carb is a Holley 500 2bbl. Bolt on swap on your 2 bbl intake.

 

[izzy jr]

Now there IS a 2 bbl you can bolt on that'll give you the same gains. I've used this carb on 4 different engines and it's a great bang for the buck. The carb is a Holley 500 2bbl. Bolt on swap on your 2 bbl intake.

Sounds interesting!

How do you identify what carb is on your car for parts? I'm pretty sure that I have a holley 2v but not sure what size and if it matters for buying a rebuild kit or not.

 

[D.Hearne]

Look at the "list" number on the front of the choke horn. A 500 is "list 4412" A 350 cfm Holley is "list 7448" The 500 has a center hung fuel bowl like the dual feed 4 bbls. The 350 comes with the side hung bowl like the list 1850 600 4 bbl.

 

[izzy jr]

Look at the "list" number on the front of the choke horn. A 500 is "list 4412" A 350 cfm Holley is "list 7448" The 500 has a center hung fuel bowl like the dual feed 4 bbls. The 350 comes with the side hung bowl like the list 1850 600 4 bbl.

K, thanks I'll have to go check that out and see what carb is on my car then.