Jus' sayin.........

quote:

Originally posted by Novacaine:
Both heads are ported. The procomps flow 365 @ 700 and the 049's I think 320 at 700. I was told don't go over 700 lift on steel heads because they wont make any more power after 7000 rpms.

That right there is the answer to me. The heads that flow 45 more CFM should make way more power and lighter to? There is your answer. I thought the aluminum heads would flow more but that is a significant difference and will be much better.

quote:

Originally posted by Curly1:

quote:

Originally posted by Novacaine:
Both heads are ported. The procomps flow 365 @ 700 and the 049's I think 320 at 700. I was told don't go over 700 lift on steel heads because they wont make any more power after 7000 rpms.

That right there is the answer to me. The heads that flow 45 more CFM should make way more power and lighter to? There is your answer. I thought the aluminum heads would flow more but that is a significant difference and will be much better.

Curly, FYI, flow is not king, it's about 4th on the list for making power! Everyone gets mesmerized by large flow numbers!

In this case there was no mention about pistons! The 049 heads have a 110 cc chamber and the procomps 120 so there will be a loss of power from the compression loss.

All in all the loss of 75 lbs of weight will be the largest factor of how the car runs vs the head swap. Without the specific engine details, it's possible the head swap power wise could be close to a wash to little HP gains for the procomp's. Also he needs to take a close look at the exhaust port exit shape and size vs his headers! Could be a big mismatch here!!!

When I ran a 496 I used a set of Dart 325's that Reher-Morrison ported to 357cc with 2.25/1.88 valves. I'm not familiar with Pro Comp Heads or how many variants they offer but if you are using anything on a 496 I would suggest and staying within that 357-360cc range with 2.25/1.88 valves. The cam I ran with those heads is fairly close (it was a little bigger) to the cam you currently are going to use.

Bob

quote:

Originally posted by RPROGAS:
When I ran a 496 I used a set of Dart 325's that Reher-Morrison ported to 357cc with 2.25/1.88 valves. I'm not familiar with Pro Comp Heads or how many variants they offer but if you are using anything on a 496 I would suggest and staying within that 357-360cc range with 2.25/1.88 valves. The cam I ran with those heads is fairly close (it was a little bigger) to the cam you currently are going to use.

Bob

Size alone doesn't tell the story, but that seems way too large for a 496. I feel like a port that big will be lazy.

I tend to skew small on cylinder head. They don't wow on the dyno but tend to ET well.

quote:

Originally posted by Lenny5160:
Size alone doesn't tell the story, but that seems way too large for a 496. I feel like a port that big will be lazy.

I tend to skew small on cylinder head. They don't wow on the dyno but tend to ET well.

A friend found this out lately with his heavy 10 sec. Chevelle with a 509 BBC. I don't remember the exact port sizes they were somewhere in the 360 range. He downsized to the low 320 range & immediately set their best 60'/ET for the car.

2BKING

The Procomp has 300 runners 115 CC. Flows 365 @ 700. The 049 are 119 CC flows 320 @ 700 not sure on intake runner.Sometimes the Xtra weight doesn't necessarily hurt et.

quote:

Originally posted by TOP38:

quote:

Originally posted by Curly1:

quote:

Originally posted by Novacaine:
Both heads are ported. The procomps flow 365 @ 700 and the 049's I think 320 at 700. I was told don't go over 700 lift on



steel heads because they wont make any more power after 7000 rpms.

That right there is the answer to me. The heads that flow 45 more CFM should make way more power and lighter to? There is your answer. I thought the aluminum heads would flow more but that is a significant difference and will be much better.

Curly, FYI, flow is not king, it's about 4th on the list for making power! Everyone gets mesmerized by large flow numbers!

In this case there was no mention about pistons! The 049 heads have a 110 cc chamber and the procomps 120 so there will be a loss of power from the compression loss.

All in all the loss of 75 lbs of weight will be the largest factor of how the car runs vs the head swap. Without the specific engine details, it's possible the head swap power wise could be close to a wash to little HP gains for the procomp's. Also he needs to take a close look at the exhaust port exit shape and size vs his headers! Could be a big mismatch here!!!

The pistons are SRP , 12.5 on 119 cc heads.

The chamber size difference is worth 1/2 point of compression assuming 119 vs 115.

The oval port Comp heads should have more material in the roof of these ports to help strengthen this area. Your cam is mild which will also help with the cracking issues previously posted.

Weight loss of 75 lbs will impact your performance plus this loss is off the nose of the car! So it will help the launch a bunch.

The only concern I have besides the overseas castings, is the exhaust port exit! From the pictures I have seen, you need to see how they match up to your headers. There could be an issue here depending on your header size, need to pay close attention to the top half of the port and make sure the header flange doesn't block off the exhaust port exit. Assuming you have no issues here, the AL heads will work better chassis wise and run faster on the track.

quote:

Originally posted by Alaskaracer:



Jus' sayin.........

Well, that's too cool for me.

quote:

Originally posted by TOP38:

quote:

Originally posted by Curly1:

quote:

Originally posted by Novacaine:
Both heads are ported. The procomps flow 365 @ 700 and the 049's I think 320 at 700. I was told don't go over 700 lift on steel heads because they wont make any more power after 7000 rpms.

That right there is the answer to me. The heads that flow 45 more CFM should make way more power and lighter to? There is your answer. I thought the aluminum heads would flow more but that is a significant difference and will be much better.

Curly, FYI, flow is not king, it's about 4th on the list for making power! Everyone gets mesmerized by large flow numbers!

In this case there was no mention about pistons! The 049 heads have a 110 cc chamber and the procomps 120 so there will be a loss of power from the compression loss.

All in all the loss of 75 lbs of weight will be the largest factor of how the car runs vs the head swap. Without the specific engine details, it's possible the head swap power wise could be close to a wash to little HP gains for the procomp's. Also he needs to take a close look at the exhaust port exit shape and size vs his headers! Could be a big mismatch here!!!

What are 1-3?

quote:

The Procomp has 300 runners 115 CC. Flows 365 @ 700. The 049 are 119 CC flows 320 @ 700 not sure on intake runner.Sometimes the Xtra weight doesn't necessarily hurt et.

acording to this the procomp has 115 chamber and more flow.it should be the better head disallowing other issues with the casting.i would want 15/1 compression and it should run well,yes it needs more cam

quote:

Originally posted by Bucky:

quote:

Originally posted by TOP38:

quote:

Originally posted by Curly1:

quote:

Originally posted by Novacaine:
Both heads are ported. The procomps flow 365 @ 700 and the 049's I think 320 at 700. I was told don't go over 700 lift on steel heads because they wont make any more power after 7000 rpms.

That right there is the answer to me. The heads that flow 45 more CFM should make way more power and lighter to? There is your answer. I thought the aluminum heads would flow more but that is a significant difference and will be much better.

Curly, FYI, flow is not king, it's about 4th on the list for making power! Everyone gets mesmerized by large flow numbers!

In this case there was no mention about pistons! The 049 heads have a 110 cc chamber and the procomps 120 so there will be a loss of power from the compression loss.

All in all the loss of 75 lbs of weight will be the largest factor of how the car runs vs the head swap. Without the specific engine details, it's possible the head swap power wise could be close to a wash to little HP gains for the procomp's. Also he needs to take a close look at the exhaust port exit shape and size vs his headers! Could be a big mismatch here!!!

What are 1-3?

Port shape - minimize velocity gradients
Average port velocity
Short Turn Apex velocity

You can have the same port flow with two different sets of heads on the same motor and see over 50 HP difference when you mess up the 3 things above!