[NAIRB]

I'm not trying to destroy your thread or to insult you. I'm just giving you a factual and real-world advice.

I sell about 40 pair of cylinder heads a month and I do port work on a daily basis. You definitely can run L-98 heads, just don't expect to easily achieve 500 ponies.

Anything can be accomplished, but at what price?

My advice is that it will be more cost effective per dollar to sell your L-98 heads and get something that is much more suited to your application.

You really need a minimum of 200 CC runner size. I saw some brand new Brodix aluminum heads on a close out at $600.00 per pair bare.

Now, those kinds of deals are out there if you shop around.

However, if you really want to use your existing heads, there is no doubt that you can, but again, I'm just being realistic about achieving 500 horsepower.


Brian

[johnsongrass1]

I gotta agree with Nairb.


With all the mag making hype about power production and how affordable it is this aggressive marketing stratagy has led people to beleive that 500hp is an easy mark to make. But if these people who claim it take it to a unbiased dyno operator, it's easy to see it ain't as easy as 1, 2, 3, but still possible. Most can't do it with strictly bolt on part's. Or make it without huge rpm and reducing reliablity.

[Elevinpointsixtoone]

NAIRB...wasn't trying to bust your nuts either....it was mostly a tounge in cheek response. Mabye I have not stated it clearly, going to some new heads makes the most sense and I'm starting to shop around. I have heard, and maybe you guys can comment, that the header manufacturers will not gurantee their product will fit an aftermarket head. I called Hooker when looking for my 2112's (57 chev, full length, 3/4", manual, 605 or stock steer box, no glide mounts, tuck inside frame rails, angle or straight) and they were like your not gonna use Brodix or Dart heads are you? At that point I said no and they were like "good, cuz those won't fit those heads".
Is this going to open another can of worms? Should I look at some GM fast burns or something else made by GM just to make it a no brainer on the exhaust side of things?

[xntrik]

I remember about 10 years ago when we got the new engine dyno. A lot of those 500 hp engines only made 400. It didn't take long to determine it was NOT a faulty dyno.

[NAIRB]

Originally Posted by Elevinpointsixtoone

NAIRB...wasn't trying to bust your nuts either....it was mostly a tounge in cheek response. Mabye I have not stated it clearly, going to some new heads makes the most sense and I'm starting to shop around. I have heard, and maybe you guys can comment, that the header manufacturers will not gurantee their product will fit an aftermarket head. I called Hooker when looking for my 2112's (57 chev, full length, 3/4", manual, 605 or stock steer box, no glide mounts, tuck inside frame rails, angle or straight) and they were like your not gonna use Brodix or Dart heads are you? At that point I said no and they were like "good, cuz those won't fit those heads".
Is this going to open another can of worms? Should I look at some GM fast burns or something else made by GM just to make it a no brainer on the exhaust side of things?

Are you absolutely bent on using aluminum?

[red65mustang]

500hp-11.6CR "streetable" ?????

are you sure you want to push it that far?

just for reference with quicky calculations:

3400lb car, 518 rwhp (18% loss) = 120mph qtr mile speed
3400lb car, 404 rwhp (18% loss) = 115 mph qtr mile speed
114 rwhp increase = 5 mph increase

just because you "can" doesn't mean you "should" for a street car

[Elevinpointsixtoone]

On the aluminum question, yes....its a big part of the reason why I can run slightly juiced pump gas and not pre-ignite. Pleaes note my altitude guys....5000 feet. Makes a big dif up here. By the way, the 500 HP goal is not set in stone....and definately not obtainable at 5000 feet. Rather a comparable engine at sea level would or could make about 500 HP.
Remember, I have ran this thing at 11.6 CR for a while now and it works without much issue. And, it is a toy, not a daily by any means.
My street bike is 12:1. runs on pump gas....CBR-945 RR world endurance engine....158 HP at the rear tire. She starts knockin at about 3000 feet. I can flog that thing all day with my wife on the back....again, I'm up in the high Sierra's.
If I was at sea level, this exorcise would not be happening.
Quick shopping looks like AFR most $$ then Brodix and then Dart being the lease expensive. I see lots of Dart Pro 1's on e-bay for around $1040. The flow numbers look impressive....any thoughts?

[454C10]

In general you need 250cfm for 500hp natural aspirated. Or 235cfm for 470hp.

If you want big street-able power use a turbo or supercharger.

A mild 350hp 350 can make 525hp on 7 to 8 psi of boost.

[red65mustang]

sorry I did miss your altitude!

another reference point to help? 10.5CR mild 302sbf at sea level tests 170psi, tests 150psi in Denver....roughly 12% less

so your 11.6 (200psi/sea level?) is more like 10.2....big difference

ha! tempted to recommend a hospital tank of oxygen in the trunk!

[Elevinpointsixtoone]

Or a blower! Ya I wish...I still have to paint this thing and put an interior in it. One advantage is high desert = low humidity...we lose atmosphereric pressure but not as much of a gain on the richness side. Summers run about 16% day time humidity and maybe 20-22% at night. Jetting here is not nearly as dificult as would be in CO....or the Smokey Mtns.

[automotive breath]

Originally Posted by Elevinpointsixtoone

...Quick shopping looks like AFR most $$ then Brodix and then Dart being the lease expensive. I see lots of Dart Pro 1's on e-bay for around $1040. The flow numbers look impressive....any thoughts?

I have had good success with AFR and Pro Topline (now RHS).

I have ported a few sets of Dart Pro 1's and Edelbrock's, they weren't very impressive out of the box. I haven’t seen the Dart platinum heads; hopefully they improved on the quality.

Forget about advertised flow numbers, they mean almost nothing.

[xntrik]

Originally Posted by automotive breath

I have had good success with AFR and Pro Topline (now RHS).

Forget about advertised flow numbers, they mean almost nothing.

Amen to the numbers,

my money goes to AFR and Edelbrock. Rarely more than mild cleanup porting.

[Elevinpointsixtoone]

I've been going here for flow data:

http://users.erols.com/srweiss/tablehdc.htm#Chevy

Supplied by a responder earlier in this thread....nice resource!

[xntrik]

Originally Posted by xntrik

Amen to the numbers,

my money goes to AFR and Edelbrock. Rarely more than mild cleanup porting.

Allow me to restate:

Biggest flow bench numbers do not necessarily make the most power.

[Elevinpointsixtoone]

Let me ask this then: is there a head you can you run out of the box, that would not bennefit greatly from port work? Or, which comes the closest? If I read this right....AFR and Edelbrock would qualify according to xntrik. Which do show lower CFM and if I remember around 75% on exhaust/intake ratio's. But maybe they have a great chamber design and strong velocity? I'll take a look at their mid lift flows again...something I have not really compared much of yet. BTW, thanks to everyone who has posted. I'm learning more from this exercise than probably any other thread I have started.