just curious, might be getting a 400.
heres the combo:
-zero deck pistons
-Weind action+plus dual plane intake (0-6000rpm)
-comp deh 265 cam
-straight up timing set
I figure these items will wake it up to a decent power/torque level. What do the pros figure?

 

what carby and exhaust? actual output will depend on how the advance curve compares to computer sim also.

 

stock ,the 400 is arround 170hp, you we'll need headers to make this thing go.can't be wrong with straight up and manifold,that will push arround 230 hp.what is your compression ratio? it's very hard to say, the best way it's the dyno.

 

I ran a simulation using flattop pistons and 10.2:1 CR. I used a 600 CFM carb, large tube headers, and a 265DEH cam, and 78.4 cc open chamber heads.

The torque is 445 ft-lbs@2000 RPM and peaks at 456 ft-lbs@3500 RPM. The torque curve is almost flat from 2000 through 4000 RPM.

The Dynamic Compression Ratio for this combo is 8.57:1. That is too high for pump fuel with Iron Open chamber heads. You need to dish the piston. A bigger cam will help, but that will kill the torque at low RPM. Closed chamber Aussie heads would help, but they have only 60cc chambers, so you would still need to dish the piston.

You need about a 10cc dish to get to a safe DCR on 93 Octane fuel with open chamber heads. The torque numbers will drop with the reduced compression.

 

hey those are some nice numbers! Thanks danlee, I was just looking for an estimate but thats even better....That should be good compression for propane, might loose a little power, but with propane I should be able to run a little more compression. So maybe the DEH255 along with some head decking would be more suitable...

and as far as why Im asking....I have an 87 bko now, have found a 78F150 w/400 for cheap axle swap, and I have a 81 2wd F150 with 351m up at my parents place I could use the engine mounts and other doohickies to put the 400 in the bronco. So I would end up with a 400", C6/205, D44/9" combo'd bronco.

 

I think that Propane is 105 Octane. Try this site for compression ratios:

www.edyno.com

 

Hey while you're running numbers what do you think numbers are for my 400.

Cylinders bored .030 over
Pistons are dished I think 9:1 CR
Stock heads
Edelbrock Performer Cam 204 deg int.,214deg. exh. @.050= Duration
.484" int, .510" exh. = Lift
Double Roller timing set not sure if it went in straight up or not my buddy put it in and I wasnt looking.
Edelbrock performer dual plane intake
Edelbrock 1406 Carb
Stock exhaust manifolds ,Y-pipe, 2.5 pipe no cat, 2.5" 2chamber flowmaster

 

I don't like that Peformer cam. The ramp rates are too slow.
You need headers.

Torque = 338 Ft-lbs @ 2000 RPM, and peaks at 378 ft-lbs#3500 RPM. The peak HP is 292@4500 RPM.

 

Hey not too shabby for a pretty much stock motor. Some day when this motor goes I wanna build a towing motor for it with more torque. If I were to switch to the 255 DEH cam and put headers with 2.5" duals and H pipe you think it make that much more power.

 

Torque = 443 Ft-lbs @ 2000 RPM, and 437 ft-lbs# @3500 RPM. The peak HP is 310@4000 RPM.

Larger valves and mild porting on the exhaust side will help the high RPM power.

 

Is most of that power made from the different cam. The specs are not that different between my cam and the 255deh. Also I found a header back exhaust kit that hooker makes for my truck. It is in 2.25" pipe and no H pipe you think 2.5" would be better or is 2.25" just fine.

 

The difference is due to the 255DEH cam being better for low RPM torque because the Intake valve closes at 53.5 degrees ABDC vs 66 degrees ABDC for the Edelbrock, and the overlap is 40 degrees for the 255DEH and 67 degrees for the Edelbrock.

 

Hey thanks for all the info I may start with headers I really like the numbers for that comp cam but dont feel like tearing into the motor again maybe I'll go find a jusnkyard motor and slowly build it to get my towing motor. Do you think you could get decent fuel mileage with that setup. I currently get 10mpg highway unloaded running 36" tires and 4.10 gears and c6.

 

You might pick up a little mileage, but not a lot.

 

very very interresting numbers