What do I use to messure the valves in a head

[1 Bad Duster]

I have a set of 915s I would like to find out what size valves are in the heads. They have the Casting number of a J head but it looks like a U. The heads came off a 1970 340 and there orange in color. They didn't go to blue till late 71 up..The Intake and the Exhaust Valves are almost touching.. Thanks Jimmy.

 

[Mrmopartech]

Its called a vernier caliper,used for measuring,mrmopartech

 

[PanGasket]

A vernier caliper would be the best tool for the job IMO
Available at any autoparts store, but I suggest you get a decent one

 

[oldkimmer]

........If there almost touching they should be 2.02s.......looks like any gap at all 1.88s.........kim....U is a 2.02 intake valve......

 

[moper]

A ruler would work. They're eitehr going to be a little bigger than 2", or a litle less. And '70 vintage 340 heads regardless of letter/casting should have 2.02s. U or X is what I'd expect to see on a '70 engine, with Js maybe on a later dated 70 assembly or '71.

 

[1 Bad Duster]

Thanks for the helpful info.. I will use the ruler way first..

 

[1 Bad Duster]

A ruler would work. They're eitehr going to be a little bigger than 2", or a litle less. And '70 vintage 340 heads regardless of letter/casting should have 2.02s. U or X is what I'd expect to see on a '70 engine, with Js maybe on a later dated 70 assembly or '71.

I did the ruler test and they look to be at 2 or a tiny more. I have another set of magnum heads they probably have 188s they don't even come close to 2"..

 

[Locomotion]

I have another set of magnum heads they probably have 188s they don't even come close to 2"..

OEM Magnums would be 1.92"/1.625" and thinner stems. Totally different head assemblies.

 

[1 Bad Duster]

OEM Magnums would be 1.92"/1.625" and thinner stems. Totally different head assemblies.

Thanks I was just checking to see where the magnum head valves came on the ruler. So if the 915 U head was at or a tiny bit past so there 202s right..

The heads on the 73 340 I'am using have 587 heads.

 

[Locomotion]

Yes, the OEM 915 U heads would likely be 2.02. OEM '73 587 heads should be 1.88.

 

[1 Bad Duster]

Yes, the OEM 915 U heads would likely be 2.02. OEM '73 587 heads should be 1.88.

Thanks again..So the 915 are going on the motor it should be a better head. I can't wait till I get this car finished for I can enjoy it driving it on the street and racing it at the track.

 

[Locomotion]

Well, it all depends on the condition of the heads, how many valve jobs they've had and what you've done to the engine and drivetrain.

* Even with a new quality valve job, if a head has had several and the valves are sunk, it will flow less air.

* You can take a worn out 1.88" valve head and regrind it for a 2.02" valve and it will flow better because the seat is nice and high in the chamber.

* A 2.02" valve will work better at higher rpms, say 6,000+. But a 1.88" has the potential of running faster because it can provide more torque through the low end and mid-range, where your car spends most of the time in. (Area under the curve.)

* If you do get new valves for either head, use stainless nail-head style valves. They flow better on the intake side. Exhaust usually like more of the OEM tulip style, but it isn't a big difference.

So lots of little things to look out for.

 

[1 Bad Duster]

Well, it all depends on the condition of the heads, how many valve jobs they've had and what you've done to the engine and drivetrain.

* Even with a new quality valve job, if a head has had several and the valves are sunk, it will flow less air.

* You can take a worn out 1.88" valve head and regrind it for a 2.02" valve and it will flow better because the seat is nice and high in the chamber.

* A 2.02" valve will work better at higher rpms, say 6,000+. But a 1.88" has the potential of running faster because it can provide more torque through the low end and mid-range, where your car spends most of the time in. (Area under the curve.)

* If you do get new valves for either head, use stainless nail-head style valves. They flow better on the intake side. Exhaust usually like more of the OEM tulip style, but it isn't a big difference.

So lots of little things to look out for.

thanks alot I'am trying to build a 7s all motor street car in the 1/8.My buddy has a stock crank and I don't know about the rods or pistons but it has a cam/intake/carb and eddy heads with 456s and 3500 stall I believe. It ran 7.22 in the 1/8..