Pump gas Engine

[Fisher1]

How would it be possible to build a 900hp pump gas motor to be sprayed with 300 hit of nitrous and live to compete in the Pump Gas wars and maybe to run in True street???
I already have a Bowtie BB Chevy dart 360 heads the car already runs 9.60 on motor 8.62 on 1 gun. But of course It has big compression and on Race gas. Where would I go from there?? I know camshaft selection plays a big roll in the equation.
Any help would be appreciated.
Thanks

[Jim Morris]

Cam selection and getting the right compression ratio. I'm just guessing. Gonna need a big cam to bleed off cylinder pressure.

[Fisher1]

Yea this is true and I'm willing to deal with trial and error but.....it can be costly. I just need to know where to start from as far as compression and exactly how big of a camshaft,lobe sep.etc.
Especially if I'm trying to start with what I already own.

[1967 chevelle]

I`m looking into doing a 598 11.0 to 1 pump gas deal and when i talked to Steve at LSM he said that 900 HP was a pretty tall order but that it could be achieved with the right heads and intake....

1.5 hp per cu. in. should be do able but it`s gonna take some work to get you there........

[JeffMcKC]

Easiest thing to make power on Pump gas, is to max out the cubic inches first, 632 -615. 1967 is right you are limited to HP per cube, so have lots of cubic inches to start with.

[GIT-R-DONE]

Might be best off to try and sell your top end. If your using a low deck block then build a 582. You can get away with 12:1 compression ratio and pump gas but the tune better be great and you'd better have a great cooling system. If you were to go with a nice spread port head with the 12 :1 comp large solid roller cam and carb package I don't see why you couldn't make 1000 hp. Keep in mind the induction system (heads intake) will not be cheap. Race Flow Development (curtis boggs ) could set you up with heads and intake needed to do the job.

[redvictor]

made an easy 890hp on 93 pump with out of the box Dart 355's and 10.5 to 1 on a 598 BBC.Cam was from Cam Motion.12 to 1 is WAY too much for reliability.
Engine was very streetable and made tons more on 2 stages of nitrous,
Ran 8.2 @ 177mph at 3250# and on MT sportsman pros.
Too much compression = retarded timing and lost power.Lower compression and nitrous work...

[Fisher1]

Gentlemen Thank you for your input. Cubic inched seem the way to go. With anything from 12 to 1 to 10 to 1.
As far as hesad flow is concerned would a large head be to much on a no compression motor??? Let's say 350 to 380 cfm??

[redvictor]

Gentlemen Thank you for your input. Cubic inched seem the way to go. With anything from 12 to 1 to 10 to 1.
As far as head flow is concerned would a large head be to much on a no compression motor??? Let's say 350 to 380 cfm??
head flow isn't the issue.It's combustion chamber size.I milled the Dart heads .045" to reduce the CC to 112cc to use flat top pistons.That's one of the keys to efficient combustion IMO.Too large and detonation becomes a worry.......

[Fisher1]

So it's safe to say the head can flow big #s as long as the combustion chamber isn't huge so to speak?
Does rod length play a part in this as far as making as much torque as possible??

[1967 chevelle]

I talked to Curtis at RFD and he told me that the heads will be set up for the engine cubic inch first, then take into account the compression second.....

The motor is still BIG regardless of it`s lack of compression.......

[1967 chevelle]

Redvictor,

Would you care to share any more info on that particular 598 combo?????????????

[Fisher1]

So true!!!! Thank you very much. I think I have half the battle won with my current head. I just need to build the short.

[1967 chevelle]

As far as hesad flow is concerned would a large head be to much on a no compression motor??? Let's say 350 to 380 cfm??


The heads i talked to Curtis about flowed 475 cfm......

So no i don`t think that 350-380 is too much........maybe too little????????

[redvictor]

Redvictor,

Would you care to share any more info on that particular 598 combo?????????????
yes,it was large...:-D
4.5 stroke x 4.6bore
Scat 4340 crank
Eagle rods with L19 bolts 6.535 long
Diamond flat top pistons(off the shelf)
Hellfire rings
Clevite H series bearings
Dart 355 CNC heads with 112cc chambers st/st 2.25in 1.94 ex valves.10.5 to 1 comp ratio
Cometic .040 thick gaskets
Cam motion custom roller 112 seperation. 280in 292ex 730 lift
GZ motorsports super pro vacuum pump.
Wet sump with Chevy oil pump.
Edelbrock Victor 454R cnc ported manifold.
Crane 1.7 gold rockers with a Dart stud girdle
Chuck Nuytten 1300cfm Holley dominator
460gph Product engineering fuel pump for engine only.
Top gun fogger and Robert Lane plate kit
All screwed together with loving care by me.....
I'd say that was comprehensive enough...lol
Now if you'd aslked about the current engine...:-D
Put the thanks in the reply..LMFAO

[1967 chevelle]

Here`s the thanks in the reply..............THANKS!!!!!!!!!!!!!!!


Sounds like a bad ass piece ...

And YES it was LARGE.....


P.S. How is the rebuild going and did you make your race?????????

No engine details necessary............

[redvictor]

Here`s the thanks in the reply..............THANKS!!!!!!!!!!!!!!!


Sounds like a bad ass piece ...

And YES it was LARGE.....


P.S. How is the rebuild going and did you make your race?????????

No engine details necessary............
No problem,hope it helps some...
Rebuild is nearly there and the race is in Canada in 3 weeks,but the car needs to go on the boat next week.
No engine details given..:-D