What is a good combo for turning high rpm?

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1lostsoldier

1lostsoldier

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I wanting to build a high rpm small block this winter for some scca road racing I've been doing over the past year. Anybody have any good proven engine combos that will turn to around 8k and be reliable? Or am I asking to much.
 
1lostsoldier said:
I wanting to build a high rpm small block this winter for some scca road racing I've been doing over the past year. Anybody have any good proven engine combos that will turn to around 8k and be reliable? Or am I asking to much.
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Any reason it has to spin to 8K rpm? I mean if you can make the same HP/TQ at 7K or 6.5K with a little bigger stroke you reliablity goes up a ton and your costs go down.
 
Well I have found so far that the higher you can rev the engine road racing the less you have to shift. So to put it in perspective when I run road Atlanta there are 3 spots that if I could rev about 1k higher than my 6700 rev line I would totally eliminate a shift.
My budget is ~7k and I have a solid 318 roller motor right now
 
Oh I'm not looking for a horsepower king either 400-450hp would be plenty.
 
1lostsoldier said:
Well I have found so far that the higher you can rev the engine road racing the less you have to shift. So to put it in perspective when I run road Atlanta there are 3 spots that if I could rev about 1k higher than my 6700 rev line I would totally eliminate a shift.
My budget is ~7k and I have a solid 318 roller motor right now
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At 8K rpm would need close to $1K worth of valvetrain alone. Oiling is a big issue too at that rpm. What oil pan do you have? Better be a road race one with gates in it like these: http://www.milodon.com/oil-pans/road-race-oil-pans.asp

Are you using you existing block and parts as a start and a $7K budget after that? Maybe you need to list what you have to work with.

I'd talk with Tim Werner or AndyF about the shift point deal. The gain might not be what you expect. Or it may be. I don't know. But they would have a good idea. They just went from a 360 to a 427 stroker. Car went a lot faster at Portland Raceway.
 
Just throwing stuff out there....

Might also want to ask your clutch assy manufacture if your setup is up to 8K rpm shifts.
 
autoxcuda said:
At 8K rpm would need close to $1K worth of valvetrain alone. Oiling is a big issue too at that rpm. What oil pan do you have? Better be a road race one with gates in it like these: http://www.milodon.com/oil-pans/road-race-oil-pans.asp

Are you using you existing block and parts as a start and a $7K budget after that? Maybe you need to list what you have to work with.

I'd talk with Tim Werner or AndyF about the shift point deal. The gain might not be what you expect. Or it may be. I don't know. But they would have a good idea. They just went from a 360 to a 427 stroker. Car went a lot faster at Portland Raceway.
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Right now I'm running 318 with a stock forged crank, eagle forged 4340 I beam rods, speed pro forged flat top pistons 3.91",RHS x heads with 2.02i 1.62e and mildly ported, Harlan sharp 1.5 roller rockers,6.1 hemi beehive springs, Crane hydraulic roller cam 300/308 .548/.558, eldebrock victor intake, 4150 650 carb, milodon road race oil pan, 2 quart oil cooler, 2 quart accusump and msd distributor and 6aln box.

right it pulls pretty strong to 6700 then it just gives up

thanks for any help.
 
autoxcuda said:
Just throwing stuff out there....

Might also want to ask your clutch assy manufacture if your setup is up to 8K rpm shifts.
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I'm running a tilton 7.25" 3 disk clutch and a tex racing T101a 4 speed which is standard Nascar stuff so it should hold up.
 
What gears are you running in the rear and trans? What type of tracks do you normally run? W ehave Lime Rock up here and there isnt enough room to really stretch out...
 
looking at what you have now engine wise, there's not enough head, too much piston, and not enough carb to rev much higher.
 
moper said:
What gears are you running in the rear and trans? What type of tracks do you normally run? W ehave Lime Rock up here and there isnt enough room to really stretch out...
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I mainly run Road Atlanta but I also run Roebling road and sebring.

I have a winters rear end with gears from 2.70 to 4.88 and about every combo in between. My trans has a final ratio of 1:1. At road atlanta I can get up to about 135mph with this car and my ex winston cup car around 180mph. But my issue isnt with top speed its with the 4 to 5 higher speed corners in which I have to up shift and it unsettles the car. Another 1k in rpm whould completely eliminate that. There are several guys in my class that have small block chevy that rev to around 8k and they shift about 30-40% less than me and I'm always chasing them.
 
moper said:
looking at what you have now engine wise, there's not enough head, too much piston, and not enough carb to rev much higher.
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I agree I dont have enough head but I'm not really worried about my current setup but rather I'm interest to know if anyone has any proven small block setups that will turn some rpms and not come apart.
 
Let me guess, Down through the Esses, turn at the base of the hill leading to the front straight and the turn coming under the bridge. Maybe the turn leading to the back straight.

I know they reconfigured the track and kind of pussified it IMO. Nothing like bombing into the gravity cavity at 180 or so... on two wheels!

Since they reconfigured it, I'd figure torque would be the way to go. Gear it higher and let the torque pull hills. I built my bikes for really broad torque when there. I'd think that would be a bigger issue now since the really, really long run is gone.
 
What type of car is this? A Cup type chassis? What does it weigh? Are there any CID restrictions?
 
A two stroke Yahama motor.
 
moper said:
What type of car is this? A Cup type chassis? What does it weigh? Are there any CID restrictions?
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Its a 71 demon (my other car is a 1990 cup car) weights ~3200 lbs
my class has no restriction on anything the class is SPO.
 
More head, more carb, and a solid roller. Maybe your rotating assembly in a 340 block, the bigger bore size will eliminate any valve shrouding problems that seem to pop up with the small bore motors. If you're gonna spin that fast, you should be making power at that rpm. If it's going to lay down after 6700, that extra 1300 is going to be a long way up the road.
 
I guess this is super secret squirrel stuff cause it seems anybody with real experience with a screamer isnt sharing and I respect that. I guess I may have to go the sb2 route or the ls route.
 
1lostsoldier said:
I guess this is super secret squirrel stuff cause it seems anybody with real experience with a screamer isnt sharing and I respect that. I guess I may have to go the sb2 route or the ls route.
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Ouch.
I am actually really interested in the responses you do get. I went the stroker route on my 340. I used the lightest stuff I could come up with on my budget. The heads were worked within an inch of their life. The current cam is a solid flat tappet cam using a couple of Ford circle track lobe profiles. It has a torque curve that looks more like a table top. I'm running a Strip Dominator intake and currently playing with a Holley 780 carb. It spins up pretty quick, but it's pretty much done around 6 to 6500.

Hence, I would think the shorter stroke would spin up wicked quick. Add in more cam and a better flowing top end, you should be within spittin distance of your goal and still making reasonable power. Just make sure you have a good oiling system and really look at your valvetrain stability at that rpm.
 
Well.....I think you've asked a very general question. what do you mean by "combo"? I mean.....anybody can read a catalog or call Summit and get a recommendation. Know what I mean? But those guys ain't gonna necessarily tell you what mods to make, and so on. First off, a DAMNED good oiling system is in order. I recommend Guitar Jones' thread found here:

http://www.forabodiesonly.com/mopar/showthread.php?t=103623


You can use those mods on pretty much anything. What a great guy to share that. He did an awesome job. I have built similar engines in the past. I would add that it is also smart to epoxy screens in ALL of the drain back holes on the heads and block. This keeps small parts from falling into the reciprocating assembly and causing major mayhem. I think Guitar Jones made mention of that in the article. One other thing that you can do to help trap small parts in the event of a valvetrain failure. Expoy some STRONG magnets in the heads adjacent to the rocker stands and shaft as well as the valve springs. Also epoxy some in the intake valley as well. Rare earth magnets work well. As for a "combo" regarding parts choices, I would recommend talking to someone like Indy or Hughes. Just remember, you're gonna have to sift through sales hype to get the info you need. Most companies will automatically try to push a product your way while givin advice. Kinda can't blame um with the economy in the toilet. Hope that's what you were lookin for.
 
Just some random thoughts... But if your goal is 400ish horsepower building for 8000+ isnt feasible. You will be making much more than that if you need power up at that rpm. Also, the budget needs to be larger. You can't do a decent long lived package IMO for $7K. The top end is going to cost you 3-4K, and the crank will run another $1500+ unless you find a decent one second hand. It might make sense to buy a used up P7 or W9 engine and de-tune it, but event hat's going to cost more than $7K and you'll need custom headers and possibly custom engine mounting. If you stay with an LA based engine, I'd stay conservative on the stroke, lighten the bobweight, plan for oiling and cam mods, and big heads. I'm not sure you can get an LA done that will live up there for $7K. Rev it, yes. Make power and be usable up there... I don't think so.
 
1lostsoldier said:
I guess this is super secret squirrel stuff cause it seems anybody with real experience with a screamer isnt sharing and I respect that. I guess I may have to go the sb2 route or the ls route.
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No, not super secret. But it took a few more questions to get an idea of what you're aiming for. Not to mention what you want to put it into.. The car sounds wicker cool....lol. I dont think a big stroker is what you want or need if you are comfortable with the rpms you're using now. But it's going to take some good work and parts to make power at that rpm. Another thought would be to gear the car so you can keep the rpms lower and build a bigger inch small block to haul it around.
 
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