I am having some work done on my Vortec BBC heads. They are off of a '96 454. I am having 2.19 intake valves installed and the intake ports worked a little. I'm also having an Edelbrock RPM Air Gap intake matched to them. My question is it worth the extra $100+ to get 1.88 exhaust valves installed? Butch Patterson at Competition Products said that doing the intake work will be worthless without the exhaust valves and additional porting. By the time they will be done with them I'll have $750 in the iron heads. Is it really worth it? Should I just bite the bullet and get a set of Brodix heads and mill the hell out of them to get back to 9:1CR? I will probably be going with the ZZ502 cam will I still be able to make 400rwhp without the additional work on the heads or is it a lost cause?

This is why I went with Merlin cast-iron ovals instead of reworking my good -781's..

But I am also running the needed open chambered low domed pistons to get me at the CR. I wanted so that cost should be factored in here too..

Mine's about a 9.8 to 1, (using .022" shims), 496" motor..

pdq67

Making 400HP with a 454 should not be a problem with stock valves. Being a 96 that would make your motor a Mark6 correct???? If so U can bolt the older gen4 heads on a mark6. Not sure chamber size on your heads but if U ran #215's or #290's they should bump your compression and help U relize the 400-425HP youre looking for at a resonable price.

The factory heads are 100cc and yield a 9:1CR. I've been told on the net that the Vortec heads are good to 550hp, but local shops are telling me 350hp unported and 375-400 with extensive porting. I just want 12's on a budget. I couldn't do it with a small block, I was hoping to be able to do it with a big block. I guess I'll just have to save up the $10,000 to build a real motor.

Check out Feb. '98 Chevy High Performance.

Exhaust ports are exceptional! You only need to narrow and blend the exhaust valve guide. The exhaust is small, but efficient. I intend to use a single-pattern cam. The intake side needs much more help than the exhaust.

I'm curious about the bigger valves, though. The chamber is so tight around the existing valves, I'm not sure you're helping anything by going bigger. I chose to stay with stock sized valves on my engine.

1st off,I wouldn't waste money on getting the intake manifold port matched,and 2nd you don't need big valves in a 454 to get into the 12's
You said budget 12's and then you mention Brodix :confused:
JMHO and experience..my 454 cost me $2500 to build..ET in signature..no big valves and Performer intake..and no gear
BTW,these machinists don't race do they? Do they have experience running these heads on a street car at the track? I hate when people want to sell you things you don't need :mad:

Not trying to sound abrasive,please don't take offense.

When I had my Closed Chamber 290 heads done, we used the stock valve sizes but installed the hardened seats on the exhaust side which by doing so allowed us to bring the valves back to what would be considered a normal height as the valve seats had sunk in a good bit from wear and previous valve jobs. On the intake side, we just installed larger 2.19 Int. valves which allowed us to reset the seat height to a reasonble level also. As far as flow - I just did a basic blend below the seat and into the runner on both the int. and exh.. Nothing too major, just a good clean-up. I will be running a split duration cam, with 10 degrees more exhaust timing to make up the difference in port flow that may be present.

When I had my Closed Chamber 290 heads done, we used the stock valve sizes but installed the hardened seats on the exhaust side which by doing so allowed us to bring the valves back to what would be considered a normal height as the valve seats had sunk in a good bit from wear and previous valve jobs. On the intake side, we just installed larger 2.19 Int. valves which allowed us to reset the seat height to a reasonble level also. As far as flow - I just did a basic blend below the seat and into the runner on both the int. and exh.. Nothing too major, just a good clean-up. I will be running a split duration cam, with 10 degrees more exhaust timing to make up the difference in port flow that may be present. These will be installed on a 408 BBC where the larger exhaust doesn't really add much below 6K anyway on an engine this size.

I think the L-29 heads are only 130 cc's or so, therefore small, large ovals!!

CHP compared them to the old peanut port heads that are generally like around 200 or so cc's, not the good -215's at 255 to 260+ cc's!!

Or even the open -781's and -049's...

Please think about this for a minute, it might help you out..

pdq67

Originally posted by mr 4 speed:
1st off,I wouldn't waste money on getting the intake manifold port matched,and 2nd you don't need big valves in a 454 to get into the 12's
You said budget 12's and then you mention Brodix :confused:
JMHO and experience..my 454 cost me $2500 to build..ET in signature..no big valves and Performer intake..and no gear
BTW,these machinists don't race do they? Do they have experience running these heads on a street car at the track? I hate when people want to sell you things you don't need :mad:

Not trying to sound abrasive,please don't take offense. These guys are hardcore. They told me I was crazy to even mess around with a stock 454 and just build a 496 or 540 right away and get the big chiefs or Canfield 360's. They also told me I was crazy for wanting to keep my valve lift under .570 so I can use factory type roller lifters. They don't fool around. The problem with our local machinists are that either they only do stock rebuilds or race engines. One place wouldn't even touch my heads and doesn't use any hydraulic cams at all. A guy I work with has a "pump gas" 540 they build that makes 650hp at the rollers.

All of my projects start out a budget builds and end up costing me a ton. I was told that the vortec heads are only good to 4500rpm in stock form, no matter what cam I installed. I want to install a ZZ502 cam just for reliability and price. I know that this choice is a compromise between performance and price. I think I'll be happy to come out of this with 300hp at the wheels and my marriage.

So I guess these guys have no clue on what a basic 12 second car is all about :rolleyes: :(

Your goals are easily obtainable without anywhere near breaking the bank..would you be happy with a big block powered mid 12 second car that was totaly streetable?

If the heads are that bad buy a set of the older closed chamber oval ports they range from 96-101cc's so compression will still be decent. With the stock 2.06/1.72 valves/ 502/502HP roller cam/ decent intake and 750CFM carb the motor should easily be 400+ HP on a budget. A mark6 is supposed to accept any Gen4/Mark5/Mark6 big block head.