I got to the track this weekend, car ran pretty good but only MPHd at 116 MPH. I thought that was weaker than it should have been. ET was 11.71.

Race weight is 4220.

Running a 4 speed and 3.54 gear with 28" drag radials, so it really wasn't strong off the line, but thought it would be producing more steam at the big end.

So far, this is where I am.

526 CI 440 source kit, 10.1 CR, quench at .046

Mopar 337 intake polished with ports matched, 850 Mighty Demon annular

Trick Flow 240s, Trick flow heads, ported 246 cc runners
INT
1. 99
2. 170
3. 243
4. 306
5. 340
6. 352
7. 370
Doug's D452 headers, 2" primaries, 3 1/2" collector I ran the 3" TTI exhaust connected.

Cam is 260/264 @ 50, .616/.620 108 in at 104
https://www.summitracing.com/parts/hrs-720152-08/overview/

Mancini 1.6 rockers

I am running the lash @ .014 instead of .018, lots quieter.

Running at 36 degrees total, in by 2800 rpm

Car feels like it pulls strong to 7,000 rpm after it gets rolling.

Checked vacuum running through the gears, even @ 7000 rpms, the gauge does not come off zero.

AFR stays right around low 13s down the track.

Compression is 175 across the cylinders.

Did I make a bad choice on the cam? The people I checked with before building gave it a thumbs up.

Wallace calculator says a little better than 500hp,what should I try to make more power at this point.

Although I don't have any dyno simulator, I was thinking closer to 600 hp than 500.

I think the cam is too big for your car and gears. That is probably why your cranking compression is a little low although there could be a lot of reasons for a low cranking compression.

My old 466 ran a 236 @ 050 solid flat tappet with ported RPM heads and cranking compression was 200 psi. That engine made 550 on the dyno and 475 rwhp. I tried bigger cams in that engine but they lost toque down low and didn't make up for it at the top end.

If it was my car I'd double check everything before pulling the engine apart, but if it all checks out I'd go about 10 degrees smaller on the cam and see what happens.

In the short term you can tweak the timing a little bit. Maybe add some jet, pull some timing out and stuff like that. Sounds like you have a wideband in the car so that helps to sort stuff out. Keep an eye on the plugs also.

Are you sure the intake port match is good? I had to build my own valley plate with batwing gasket holders to get the intake gaskets lined up properly with the 240 heads.

You can find out real fast if the cam is too big. Open up the lash to .018-.020 and run it again.

I think you did pretty good. Take 1000 pounds off that car and its in the 10's easily without much gear or compression. Pretty impressive.
Cam in my little 360 is 260@50 as well and its just a touch over 10 to 1 itself. At over 500 inches hard to believe your cam is " too big"
How do you launch the car and what rpm is it crossing the stripe at?

What where your sixty foot times?

4220 is a lot on weight to get moving, especially with a stock gear. I can see a lot of breakage in your future. At 3200 lbs.my .Barracuda 440 source pump gas 505 runs 10.30 at 130 with 4.56 gears . So if the calculation of .1 tenth per 100 pound loss your into the tens. My advice is to loose weight, change the gear to maybe a 4.10 if this is street / strip car more gear if strip only.

Lots of cam and head flow, but perhaps not enough carburetor to feed the RPMs they want. With a heavy car, you may have been better off focusing on midrange torque than top end hp (??). With that said, Don’t let yourself get disappointed the first time out. It takes trial and error to find what makes each combo ET. That’s a lot of weight you’re pushing; you’re really going to have to have the chassis work well to get 4220 to ET effectively. My car goes 3820, and I thought it was a load.

I'll play with the timing a little bit and maybe give it some more jet.

The intake and heads both looked good on the MW sized gasket, although I was sucking some oil past the gasket, and had to use some motoseal to get it to seal up.

I read a post you made a while back, where a 337 intake kept making power over 7k. I was trying to use that as a basis to match the top end. I probably need to get a Dyno simulation program to play with. Thanks for your thoughts!

I didn't realize it would affect duration, I'll try it, thanks!

Yea I spoke to several people who agreed they did not think it was too much.

There is no way I'm going to drop 1000 pounds, but, I plan on some fiberglass bumpers and hood.

I only got 4 runs in, the best time was launching at 3500, shifting at 7, and shifting into 4th just before the stripe.
I think I was at 5100 rpms or close.

Thanks for the reply!

Hi Cab. They were 1.76ish
I can do better with some 26 inch tires and practice though.

Here's a video, you can see the rear springs working

https://www.youtube.com/watch?v=_cBwV3gCAck

I already have been looking around for 4.10s. The clutch wasn't liking the 4500 rpm launch much. Thanks for the reply!

I love your car.
My car was a bit lighter before the sub frame connectors and full exhaust. It weighs 3960 now.

Thanks for the post!

Drag radials and a 4 speed probably don't get along very well Buy another set of bias ply tires that are designed for a manual trans. and work on the 60 ft. times
Once you get the 60 Fts. in the mid to low 1.50 the MPH will pickup also due to getting the trans into high gear sooner, don't short shift it make it hook up better, so the motor will have longer to pickup MPH in high gear.

using wallace with your weight/tyre/gear and 540hp I get>
60 Foot E.T. : 1.61
1/8 Mile E.T. : 7.29
1/8 Mile Trap Speed : 93.20
1/4 Mile E.T. : 11.56
1/4 Mile Trap Speed : 116
1/4 Mile Trap RPM : 4,928
with 4.10's its 5700 trap, better...4.3's>6000, I reckon there's more in there hp wise, just got to unleash it at the right time.

As an example, I was running 13.31@101 in street/strip mode with 3.55's/26" slick and a 3500stall combo. I added, 4.30's/28" tyre, 4200stall+ better cam/carb/hdrs and went 12.39@108.6, mph shows +65hp in the motor which is not a second improvement in ET, its how/when its delivered.

With that big a cam, a 4.10 gear will help out a lot.

I think you need more carb, among the other things suggested. The various carb size calcs say 900'ish for your cubes at 85% VE, and you're probably up in the mid 90's. S/F....Ken M

Other than gear and weight, IIRC. The mighty demon CFM number is wet flow number. So in comparison to others it is a "bigger" 850.

I am surprised at how many of you w/BB guys even consider a 4150 when a 1050 Dommy on this motor would wake it up big time.........an 850 BARELY belongs on a warmed small-block...........

Thanks for all the replies,

Cab-The drag radials are dead hooking at this point, maybe a turn. They are spinning as much hitting second gear, once the engine is building steam.
60s in the 1.5x area would be great!!!!

SG Cuda - yup they sure would. Going from 28" tires to 26" should reduce the effective gear ratio to 3.8, so that will help some

EchosSixMike- I dont know about the carb. AndyF said he seen 20-30 hp going to a dominator because of a superior spray pattern. My carb isn't making any vacuum even at 7k.

FurryStump- I was told by a local carb shop he estimates it close to 1080 cfm

Dom- Yea it is in future plans. It will require removing the hood for clearance. That, and probably an electric booster pump?

I am going back out to TNT with 26" tires, without the hood, a 2" spacer, and play with timing and jetting.

I also just got a FBO box and coil to replace the orange box. I was getting some breakup over 6k.

Hopefully the driver will be better.