TC
Since I am sitting on my cover & do not want to put hole in cover no tunnel ram for me. Richard lee uses the tunnel ram base & mounts his intercooler to the base. Question is do we need to be running 2-4's or could we get same HP with one big 4. I don't know.

Update on jetting. Jetting now 68 primarys, 83 secondarys, 6.5 PV in primary only. Motor runs good, I might be losing HP but am afraid to lean down the secondarys any more. I hate the word detonation. After I changed plugs last week I notice the plugs on the odd side1,3,5,7 (secondary) are running richer that the ones on even side 2,4,6,8(primary). Transom is clean all the time now. I think I am going to try & richen up the primarys to 69 or 70 & lean the secondarys same amount. What do you think??

Back on topic. Would I procharge again? Yes!!! Yes!!!

TURBOJACK - Since your carbs are side-mounted, are the primaries on the lean side of the engine and do you think that might explain the difference?

I'm glad to hear that everything is running well. Your jetting sounds so normal, but those are 390 or 450 CFM carbs aren't they? Normal jetting in those carbs runs between 51 and 57 primary and 30 to 34 secondary, so it does make sense.

I don't know at what point the single four runs out of gas, but two 83 jets flow as much as a single 117 jet. I think you just run out of fuel metering passage area; it becomes the jet, so two carbs is an easy answer.

Transom is clean, how's the cruise and mid range punch?

Holley 450 carbs are mounted sideways, Primarys are on the clean sides & secondarys on rich side.

Your explanation for jetting makes good sense. I did not look at it that way.

Cruise is good. I normally cruise at about 30-35 MPH @ 2400 rpms. When I punch it boat jump, & motor raps to 4K, then starts climbing from there.

Remember last call I had made to procharger they said they were at 68 primary, 80 secondarys. I think that would clean up the seconary side of plugs. I guess I need to do some more passes & check plugs.

Sorry, I wasn't paying attention, you explained that in your original post. Wow, that must be some ride! You're cruising slow; is the engine happy at 2400?

Listening to you and jspeeddemon makes me want to build what I just drew. A dual carb, dual intercooler setup for tunnel ram and the M4 blower. Reduced pressure losses and 800+ cubic inches of intercooler core!! I need a rich client to pay for the fabrication. I don't care if it goes on my boat, I just want to build it!

Tom

Turbojack the tunnel ram setup I am looking at, is the type that seperates at the runners, I will email you a picture. It is 7 inches where it splits, with the intake sitting on the floor. You'll find that you mainifold and the plenum box(the small box) in your setup measures 6.75 inches, I am sure you have a 1/4 inch there to work with. This will eliminate that poor transition down thru that crappy manifold and plenum. A local engine builder who builds sheet metal intakes, looked at the transition thru the box and his comment was"This motor wouldn't even run if it was naturally apsirated", I have to agree. We are trying to fix this and will be glad to share the formula.
Tomcat i would love to be able to do a project with you, let me hit the lottery first and I'll fund your project R and D.

jspeeddemon - I think I understand where you are splitting the tunnel ram base from the carb plenum(s) and that is your height number, but do you not need a decent sized carb plenum (more than the stepped box spacer)?

I like the tunnel ram idea. I know you are planning to keep the remote intercooler, but I like the idea of splitting the flow from the compressor into two intercoolers running down either side of the tunnel ram. Bring the air in the bottom of the intercoolers and out the top. By the time you have turned the air over into the carbs with this arrangement you have definitely raised the lid of the carb box ~6", but the pressure losses would be less and the balance of flow across the intercoolers would be better. Can fit about 800 cubic inches of core this way but the whole affair would be BIG.

Hurry up and win the lottery!