Starting my new engine build soon, with some budget minded changes in place. My goal is to run 7.90's. Car should weigh in around 2,200 lbs when done. Rear gear is 4.10, using 32 x 14.5 tires. Engine combo at this point is an Indy solid RB block, and Indy -1 345cc heads. From what I have calculated, I will need about 875hp and need to go over the stripe around 7,500 rpm.
At this point the block needs to be resleeved, and since it already was sleeved for 4.560" bore, I will resleeve it at that bore. I am also thinking about a 4.25 stroke crank. That will give me 555 cubes. I am going to use as long a rod as I can find, 7.10"+. My concern is if this is too many cubes to get the rpm I need. Would a 4.500" bore or a 4.150" stroke be better for high rpm use? I'm not worried about cylinder wall thickness, this block was run previously at 605 cubes on nitrous and survived until it broke a rod. The intake setup presently has 2 850's on it but will be upgraded to 2 1150 dominators soon enough.

I know of 4.5 stroke engines redlined over 7500. 4.25 should be fine.

I know the bottom end can mechanically handle it. I was wondering what limits have been found on these heads to keep the rpm where I need.

I thought it might take a little more power than that to run 7.90's.

My 514 makes 900 hp with EZ heads and a cast 4bbl intake. My engine is 4.440 x 4.150 and peak power is around 7000 RPM.

Your heads are bigger and better than mine so you should make more power. I think either 4.150 or 4.250 stroke will work for you. You'll need a big cam to put the peak power at 7500 rpm. My cam is 282/288 so you'll need to bigger than that.

Dwayne can get you all sorted out in terms of cam, lifters and springs. I don't think you need a tunnel ram to make 900 hp. It is a lot more money and more of a tuning hassle. If it was me I'd spend the money on EFI rather than a tunnel ram and two Dominators. The EFI setup will give you data acquisition as well as precise tuning.

https://www.youtube.com/watch?v=LZcFl7fy6FI

2200 with driver? Is this a door car?
Doug

Yes. 70 'Cuda, 2x3 frame rail, C/M cage.

The moroso chart shows 890hp for a 7.90 @2200lbs.

That's as it sits on the line, uncorrected, in whatever air you're racing in at that moment.

I'd be shooting for about 950 std corrected hp......or more.

Something along the lines of Dougs motor but with a TR on it.

Why do you want to go through at 7500? A few more cubes, a taller tire or less gear will allow less stress on the valvetrain.
When I run the numbers and use my combo as a way to figure power needed, I suspect you will need more power than the -1 heads can provide. Mine shows 841 up at 2000 d's to run 8.88 at 3065 lbs. The same calculated said 2200 lbs running 7.90 at 175 would need over 900 hp. IMHO if you run in air similar to me you would be needing about 1000 dyno hp to be sure to meet your goal. That would take better heads to easily make the goal with a reliable motor.

Greg: Already running 4.10 gears with a 32x14 tire. I'm probably going to try a 33 if it clears ok, but that will only lower my trap rpm to 7150-7200. Trying to use what I already have.

Put the 4.5 in it for 587 inches. I doubt the price is any different. Why not?

Price isn't any different. The problem is can I spin the engine to the rpm I need with the heads I have or will it choke?

2200 with driver is very light. My Cuda with a 2x3 frame mild steel cage and aluminum block was 2500 with me in it. I'm doing a 4130 25.1 chassis now and I don't expect mine to be down near 2200. Mine ran 8.50's. It made just over 900 on the dyno. Cuda's have a lot of frontal area to overcome, it would be interesting to see what it would run in a more aero car at the same weight.

I'm doing a 25.3 build. The only steel body parts are the quarters, tail light panel, rocker sills and roof. I have 225lb springs in the front struts. With the comlete steel block 500, flywheel, scattershield, trans, driveshaft, rear end, and steering in place, and me standing on the front crossmember, the front springs still don't even start to compress.

Mine was also just the steel roof and quarters strut front and the bare minimum tube to meet the 8.50 cert. If you can get it to 2200 at the line you're doing real good.

Yeah, that would be exceptional with you in it.

For a car the size of a Cuda' to get around 2200#, you will have to address every inch of the car......

Round tube 4130, with minimum bars for the required cert, aluminum block, mini-rad, lithium battery, carbon shaft, carbon body panels, 4130 rear, or Mark Williams modular, everything in the rear lightened (axles, spool, ring), the lightest wheel/tire combo for its size, lightest brakes, etc., etc., etc.

You can't leave anything out and you won't believe how fast the cash register rings when trying to get REALLY light.

Well, I guess we'll see how close I come to my estimate as the car gets closer to completion.

Major weight losses so far have been :
1) Removed all excess metal from original shell including floor and firewall
2) Cast iron Hemi box replaced with magnesium DNE
3) Steel flywheel replaced with aluminum
4) Stock front end replaced with Strange strut and brake kit
5) Original frame, connectors, M/S backhalf changed to 2x3 rail
6) M/S cage changed to C/M
7) I lost 50 lbs (but gained back 20)

According to a formula I found, the kinetic energy in Parts increases at the square of the speed. 7200 rpm to 7500 rpm would be an increase of about 8 percent.
Add to that the energy and resistance to change in direction and control surge of the spring increases due to kinetic energy and that increases stress to another level .

My bet is 2400-2600 w/o driver.
Doug