Dommy vs 850 opinions

Basic combo:
512 10.3:1
TFS Streets ported not sure on flow #s
Victor 4150
Custom solid flat tappet
1 7/8 headers 3" full exhaust
3.70s 30" tall radials
4100lbs 79 f100 stock suspension

Truck ran a few 10.0s and dipped into the 9s once at 130. This is with a stock rebuilt c6, an NOS big shot plate and a Holley 850.

Truck started slowing down and found metal in the trans so I bought some used but basically new parts from someone's project. JW full bbf th400 set up, IS real street plate kit, and a pro systems dommy.

Switch the trans only and ran a 10.13 129 without the trans brake hooked up. C6 was foot braked as well. Installed the carb and plate with an adapter bc of the 4150 intake and hooked the brake up. 10.2s checked a list of things and fixed a bunch of issues. No better. Did comp and leak down. All within spec. Finally sent the nitrous kit back to IS to have it flowed. All checked out ok and sure enough didn't pick up with the new jet maps. Had the c6 and converter freshened up and swapped it back in. Picked mph back up but not the 60ft from when the c6 was previously in.

So are the carb and adapter slowing me down? Not a huge deal to go back but the 850s on my dads truck now and it just doesn't make sense. Unless the adapter is messing it up. With the 850/c6 it went 1.36 60ft. Best with dommy/th400 off the tb was 1.41. New best with dommy/c6 is 1.44.

A 4150 model carburetor will usually be easier to drive but, a Dominator will usually make more power; it is that simple.

That's why I'm confused. I've put tons of street miles on both carbs and while the 850 is better the dominator isn't all that bad after I fixed a few drive ability issues. But the 850 has made the fastest pass by over 2 tenths on the bottle. This has been over 2 years of me dicking with the truck and changing and swapping parts.

Is it spinning off the line with the added power? Is the converter correct for the combo? I can't answer your questions but seems as if it may be something other than the carb if you go faster on top end and slow down on 60 ft

I seriously doubt the Dominator is the culprit unless the carb tune is way off. Personally, I don't like taking a BBF down the track without at least one.

Did your trans swap include a converter change as well?

maverick wrote:I seriously doubt the Dominator is the culprit unless the carb tune is way off. Personally, I don't like taking a BBF down the track without at least one.

Did your trans swap include a converter change as well?

I like that,,, at least 1, hymmm instead if 2 1600 cfm, 3 1100????? wonder how that top would look??

Have you tried putting the 850 back on?

dfree383 wrote:Have you tried putting the 850 back on?

Damn Defree you beat me to the punch.

My next step is to put the 850 back on. I just rebuilt my dads old 750 so I can get my 850 back.

The c6 has no Trans brake and a matched ptc nitrous converter for my truck and combo. The th400 had a Trans brake and a ptc converter built for a convertible fox body around 3500lbs.

I have the tune on both carbs close using a wide band a/f gauge. It seems like it's lazy with the 4500 carb. Tracks are all closed for at least another month I was just trying to get some facts to back up my experience. I feel the the hp and mph should be considerably higher with the 4500 but that is simply not the case. Both carbs have been the same mph. But the 850 has been faster in et by 2 tenths

You need to use a Victor 4500 intake with the Dommy carb. Using a spacer and funneling the A/F mixture down to the 4150 size is a restriction to the Dommy carb airflow characteristics.
Some will disagree with this, and that is fine, but I've made the same swap, and it picked up solidly!!
And on a side note, the Victor 4500 intake has that funky cloverleaf mounting pad. I found more power and a much better A/F distribution when I milled out, and hand ported / blended the plenum and got rid of the cloverleaf.
With all things being equal, I suspect that your results would be very similar to mine.

I agree I thought that too and the nitrous plate is 4500 as well. But everything Ive read says otherwise. But again, it is slower now with a dominator then the 850 using the 4150-4500 adapter.

Here is a quick summary:

850, stock c6 (no brake), NOS big shot plate 9.98 130 1.37 60ft

850, built rollerized th400 (brake not hooked up), NOS big shot plate 10.13 129 1.43 60ft

Pro Systems dominator, built th400 (using brake), Induction Solution Real Street plate 10.21 128 1.41 60ft

Pro systems dominator, rebuilt c6 (no brake), Induction solution plate 10.21 130 1.44 60ft

So $3000 worth of parts and it's slower. And I'm going back to how it was piece by piece. I sold the th400 complete bbf set up already. I thought the 400 would have picked up a lot over the c6 but that was not the case. And I sent the plate back to IS and had it flowed, changed bottles, changed fills, changed the feed line, changed nitrous solenoids, changed gauges, cleaned the screen, etc. Still no gains.

130 mph, 128 mph, 129 mph 130 mph. I don't think the carb nor transmission are the road block. Not enough head? No matter your other changes, mph didn't change. MPH is your horsepower indicator, ET, is a function of launch traction, etc. Seems the car is a bracket car for a 130 mph class. Heads or cam to make a change.

A couple of Go Pro cameras are a good investment!! One under the vehicle to see how the suspension is acting, and to see if the tires are spinning, one for constantly watching the wideband 02 display all thru the run.

It's on a drag radials I know when it spins and when it hooks. They aren't forgiving like a slick.

Regardless of the rest of the combo a more efficient (so they say) trans, a better carb and better nitrous kit should not slow the truck down. And I've had ample time to dial it in as it's been since October 2013 when it made the best pass.

At this point I'm not looking to pick up I just want back what I already had. It made probably a dozen 10.0 passes at the end of 2013. After all these part changes it hasn't been a 10.0 since. I guess ill swap the carb and nitrous plate and report back my results no matter if they are positive, negative or exactly the same lol.

ET is a function of track, hook, etc. MPH is the hp. Your ET is most likly in your 60 ft, and odds are its spinning more. LOOK at the whole time slip, see where the variances are.

A 1050 is a problem on a low compression 466 on foot brake. When you mat the throttle both blades open and you have a huge amount of air available to the engine. (bog) Are you feeling this? This wont happen on a trans brake.

I missed where you tried the 1050 on the trans brake

It is low compression but it's a 512 now. But yes I feel it leave soft with the 4500. It's half a tenth slower 60ft on motor compared to the 850. It left the best with the c6 and no trans brake with the 850 on spray.

This isn't some 3 times at the track assumption. I've probably logged 100 passes in that last 2 years. And it's just flat out slower with the 4500.

I guess I'll try the 850 and some new 315 radials and see how it works when the track opens back up for the year.

Did your best runs take place in cool or chilly conditions??
You already know this, Im sure...but I know my car has ran its best times in cool weather where theres power in the air!!
Its a slug in the middle of the hot summer, even after tuning accordingly, is been off 2 to 3 10/ths, plus has the tendency to spin the tires more easily when the track surface is scorching hot.
The moral of the story to this is.....racing in the hot summer time sucks!! LOL:D

All of my best times with each combo were in the fall and your exactly right. My truck doesn't get affected too bad with nitrous though. On motor it slows down a lot in he heat.

So what is the current configuration you have it at now??...you got the C6 back in it, and the 850 carb back on it??
How much NOS are you spraying??

Current combo is the original c6 rebuilt and the converter cut open and cleaned out, the Pro Systems 4500, and the Induction solutions 4500 real street kit. It has a 90 nitrous jet now. It's around 200-250 depending on who you ask. The best pass ever was with an 82 nitrous jet and the 850 carb/ big shot plate. If it would have picked up going to the Chevy Trans I was going to keep it but it hurt me inside and if it wasnt helping it had no business being bolted under my truck lol.

Did you add any timing when you installed the dominator?

I am going to make a guess that driving manners and torque below peak power is much more important than max hoesepower in your situation.

I know on a c4 its comin to slow down on 60 ft. from normal rebuilds do to drag of high gear clutches spinning against each other and it ususally will back up over time. Do you guys know if low gear has the loss of tight clutch packs that a c4 does? I know a buddy loosened his 400t up and picked up alot in the 60 ft. I just went in and put all new bushing in and 60 ft seem to slow down a hair. Goodluck