Originally Posted by mike tkach (Post 4273430)

bb,i think top fuel is 500 inch limit unless they changed it.the nitro engine gets by with the smaller port because the nitro methane has it,s own oxygen,not relyant on oxygen from the air.i believe they only run the nitro engines to around 8000 rpm.

Originally Posted by mike tkach (Post 4273430)

bb,i think top fuel is 500 inch limit unless they changed it.the nitro engine gets by with the smaller port because the nitro methane has it,s own oxygen,not relyant on oxygen from the air.i believe they only run the nitro engines to around 8000 rpm.

Originally Posted by mike tkach (Post 4273430)

bb,i think top fuel is 500 inch limit unless they changed it.the nitro engine gets by with the smaller port because the nitro methane has it,s own oxygen,not relyant on oxygen from the air.i believe they only run the nitro engines to around 8000 rpm.

Originally Posted by Black Baja (Post 4273288)

You know I was thinking about your previous post and about using the larger than optimal intake port and how it you said it still makes good power with the right blower what Darin said about the Pro-mod engines. You know top fuel is the limit. There is nothing more powerful. They run a 525ci motor. About 2 years ago I was in a friend shop and he said let me show you something (it was a top fuel head) I checked that thing out from top to bottom. I couldn't believe how small the ports were I mean with that kind of power and boost I would think you would be able to drive a tractor trailor through them. Surely not. I've worked on Nitrous Pro-Mod stuff been elbow deep in the motors I know what kind of port it takes to support 865ci and 9000rpm (tractor fits). But the top fuel stuff is small. I guess the theory of sizing the port to the cubic inch and rpm applies no matter what's on top of it or what kind of fuel its burning.

Originally Posted by Black Baja (Post 4273464)

Rail 500" Funny Car 525"

They have injectors in the hat as well as in the cylinder. Really the only way to make BIG power is to run a dry port and inject into the cylinder. It's funny I was just having a conversation with someone about direct injection. I had some experience with a motor in the past that couldn't make any power injected on alcohol (wet runner) wouldn't go over 1300hp. Injector went in the trash for some out of the box gas Quick Fuels and it went over 1600 first hit on the dyno. This was a N/a billet headed deal.

Originally Posted by mike tkach (Post 4273694)

just fyi,the nhra rulebook sais top fuel&funny car min cu in 490-max 500.from the 2014-2015 rulebook.

Originally Posted by offshorexcursion (Post 4272223)

The pro comp head can be worked to flow good numbers.

IMO the cheap casting can not reliably handle a lot of power though.

Even with the best parts installed, shaft rockers etc, the casting will fail.