tunnel ram carb talk

[prairiehotrodder]

I'm currently running a pair of 750 track warrior holley carbs on my profiler tunnel ram. The engine is a 12.9 CR 555 big block chevy race engine. I'm guessing it makes 850 hp but never been on a dyno. I'm real happy with the carbs and they have worked flawlessly. I'm rebuilding after a crash and have purchased a few items for an engine upgrade next winter. I bought a 4.375 crank and 6.535 rods to turn the engine into a 572 or 582 depending if i am able to stay with the same bore size. There are 2 pistons that are available. Je and Wiseco both sell a 1.060 compression height piston with a 40 cc dome that should put me right at 13.57 CR which is as high as i want to go with the fuel i am using. The increase in compression from 12.9 to 13.57 and the 17 cubic inches i'm hoping should gain me 25 - 30 hp. My question is if i'm reaching the limit of the 750 carbs. Should i go to 850's ? Since i am set up for 4150 style carbs ? Or would a pair of 1050 dominators be the way to go ? Would bigger carbs help me even right now ? the heads are AFR 385's and the cam is 280/288. I'm just bench racing ideas assuming i don't crash or blow up anything this season or that the world doesn't end which i kind of hope that it does.
Brian

[ClassAct]

Why aren’t you running Dominators? I wouldn’t run a 4150 regardless of CFM rating.

[prairiehotrodder]

Why aren’t you running Dominators? I wouldn’t run a 4150 regardless of CFM rating.

I started out my tunnel ram life with an old weiand that had a 4150 flange. It worked awesome and i've upgraded tunnel rams twice since then but am still using the same carbs.

[Dave B]

You would gain with 850s but not for money spent. You would Def be happy with a pair of doms and see better improvement. I went through same thing with 900 plus hp sbc. Braswell told me when I went from 865 hp to the 935 setup that his 850s would still do the job. I ran it 3 times, about 7 passes. Went to doms and went from 8.04 to 7.87 in 1/4. Was it worth 3200.00 upgrade. Hell yes. Would it be for everyone? Who knows. It felt and acted like a whole different deal. I discussed it with him and he was amazed at gain I had. The 850s didn't miss a beat but they were out of their realm. And this was on 380 inch sbc.

[prairiehotrodder]

You would gain with 850s but not for money spent. You would Def be happy with a pair of doms and see better improvement. I went through same thing with 900 plus hp sbc. Braswell told me when I went from 865 hp to the 935 setup that his 850s would still do the job. I ran it 3 times, about 7 passes. Went to doms and went from 8.04 to 7.87 in 1/4. Was it worth 3200.00 upgrade. Hell yes. Would it be for everyone? Who knows. It felt and acted like a whole different deal. I discussed it with him and he was amazed at gain I had. The 850s didn't miss a beat but they were out of their realm. And this was on 380 inch sbc.

Are you running 2 circuit or 3 circuit dominators ? I've never really known the difference.

[Tuner]

2 circuit 1050s will be your best choice.

[Dave B]

You would gain with 850s but not for money spent. You would Def be happy with a pair of doms and see better improvement. I went through same thing with 900 plus hp sbc. Braswell told me when I went from 865 hp to the 935 setup that his 850s would still do the job. I ran it 3 times, about 7 passes. Went to doms and went from 8.04 to 7.87 in 1/4. Was it worth 3200.00 upgrade. Hell yes. Would it be for everyone? Who knows. It felt and acted like a whole different deal. I discussed it with him and he was amazed at gain I had. The 850s didn't miss a beat but they were out of their realm. And this was on 380 inch sbc.

Are you running 2 circuit or 3 circuit dominators ? I've never really known the difference.

3 circuit 850's,
4 circuit doms.. But a good set of 2 circuit would be easiest to learn with.

[Tuner]

Oooh nooo, 4 circuit 850s and 5 or 6 circuit Doms. Don't be shy. the new electric wrenches make changing plugs so easy

[Dave B]

Oooh nooo, 4 circuit 850s and 5 or 6 circuit Doms. Don't be shy. the new electric wrenches make changing plugs so easy

We have no problem with 3 circuit 4150s and 4 circuit doms. If we didn't make more power with them we wouldn't use them! When I worked with prostock carbs not a single set was 2 circuit. Did we try them ? Yes . Did we slow down ? Yes!!!!!

[Dave B]

Welcome to sloth talk,
Home of the 5/64 ring iron headed 1957 tech. Here we will beat to death 1.94 or 2.02 valves. Highly discuss my 2" flow master ex, is it too much ? Oh hell yes! Where the whole board reads articles all day and hashes out what they haven't tried but are some how deemed experts!! Be scared of tech!!!! It's evil!!!

[Walter R. Malik]

Welcome to sloth talk,
Home of the 5/64 ring iron headed 1957 tech. Here we will beat to death 1.94 or 2.02 valves. Highly discuss my 2" flow master ex, is it too much ? Oh hell yes! Where the whole board reads articles all day and hashes out what they haven't tried but are some how deemed experts!! Be scared of tech!!!! It's evil!!!

That is so true most of the time ... LOL.

Having actually done something doesn't count for much here ...

[prairiehotrodder]

I'd be happy to give a couple dominators a try, it just sucks that it will cost an arm and a leg. I have no desire to buy used carbs that have unknown problems so therefore a pair of carbs will likely cost $3000 canadian dollars and the top for my tunnel ram will be another $550. I'm not in a rush. I believe what you are saying about dominators and it seems like going to 850's is a waste of time based on what you are saying. By next winter maybe i'll have slowly pieced together the parts i need. Thanks for all your help.
Brian

[F-BIRD'88]

I'd try the carbs you have and measure intake manifold vacuum at WOT when crossing the stripe.

This is still a bracket racing car right? It won't make you any more money, and the girls will love you just the same.

I would have gone supercharged at the this point. (on methanol).

[prairiehotrodder]

I'd try the carbs you have and measure intake manifold vacuum at WOT when crossing the stripe.

This is still a bracket racing car right? It won't make you any more money, and the girls will love you just the same.

I would have gone supercharged at the this point. (on methanol).

It definitely already doesn't make money, and i'm happy with the girls i have now.

your point about checking vacuum is good and i can easily do that this summer. thanks for that idea.

I dreamed about going to blown alcohol and that would be cool. While the kids are hellbent on high tech gadgetry, I find myself heading even more into old school sledgehammer big blocks.

Brian

[mt-engines]

You would gain with 850s but not for money spent. You would Def be happy with a pair of doms and see better improvement. I went through same thing with 900 plus hp sbc. Braswell told me when I went from 865 hp to the 935 setup that his 850s would still do the job. I ran it 3 times, about 7 passes. Went to doms and went from 8.04 to 7.87 in 1/4. Was it worth 3200.00 upgrade. Hell yes. Would it be for everyone? Who knows. It felt and acted like a whole different deal. I discussed it with him and he was amazed at gain I had. The 850s didn't miss a beat but they were out of their realm. And this was on 380 inch sbc.

What was the MPH? You're saying you gained 100hp?