Upgrading Heads... what size Valves???

[74bigblock]

This winter. long with a dual plane intake I already have, I am going to swap out heads on my big block to gain some additional HP and save about 180lbs.

What would be the difference in Intake valve sizes and why would I go with a 2.25" vs 2.19"??

 

[norvalwilhelm]

The 2.25 have just a slight edge in flow. The disadvantage is the valve pocket in the top of the piston might need a bit of enlarging.
If you go with 2 .19 the pistons were cut for them and if the seats ever get rough you can go to the slightly oversize valve to salvage the heads.
The new heads are now running 2.300

 

[74bigblock]

The 2.25 have just a slight edge in flow. The disadvantage is the valve pocket in the top of the piston might need a bit of enlarging.
If you go with 2 .19 the pistons were cut for them and if the seats ever get rough you can go to the slightly oversize valve to salvage the heads.
The new heads are now running 2.300

No wonder GM is selling off the old ones cheap!

 

[74bigblock]

There is a 170$ upcharge for Stainless Steel guides and seats over bronze... is there a benefit for my application (regular driving and an occasional trip to the strip), or should I save some bucks?

 

[norvalwilhelm]

There is a 170$ upcharge for Stainless Steel guides and seats over bronze... is there a benefit for my application (regular driving and an occasional trip to the strip), or should I save some bucks?

I would go with the bronze guides. Never heard of stainless guides. As for the valve seats you will not have a problem with any of them. Even the old leaded seats survive fine with unleaded gas. Towing is what kills seats, not normal driving.