Hello All,

I received an engine that is supposed to be putting out 330+- HP and a chassis dyno pull last week confirmed that I'm getting no where near that. Dyno numbers were 195HP @ 74mph and 266ft-lb @ 81mph. Even taking into account C4 Tranny and unknown rearend parasitic losses of 20%, I'm still 100hp shot in my estimation.

I'm hoping for some help is where to start looking. Following are the sepcifics.

Block - New, not overbored steel block so actual displacement is 342 not 347 ci.
Crank 3.400 stroke Forged 4340
Rods - 5.400 length Forged 5140 I-Beam
Pistons - Keith Black 366 Dished Hyperutectic
Heads - Edelbrock AL RPM heads 60259 (60cc Chamber, 170cc runner, 2.02/1.60 valves)
Camshaft - Edelbrock Performer Plus 2122 (204/214 @0.50) Hyd Flat Tappet
Intake - Edelbrock Performer
Carb - Edelbrock 1406 600cfm
Rockers - 1.6 Pro Magnum Rollers
Timing Chain - Comp Cams Roller chain
Ignition - Pertronics Igniter2

Timing currently set at 12BTDC maxing out at 27deg

Cylinder pressures are:
1 - 128#, 2 - 135#, 3 - 135#, 4 - 132#
5 - 132#, 6 - 125#, 7 - 128#, 8 - 135#

Anyone willing to venture out and tell me where I might've messed up?

Thanks in advance
Tom

 

your cam is way too small, your intake is too small, your carb is too small and the wrong brand, and lastly (and most easily corrected) is your timing isn't advanced/advancing enough. you should have 10-12 @ idle and 34-36 total.

 

Tom, who built your engine? I agree with my77, the components are not well matched.

 

m77 is right on..

 

and next time go to a dyno that gives you HP and torque at your RPM level....not at your MPH...that is pretty useless information....if you get the information based on RPM you can calculate the theoretical optimum shift points. Not that everybody does that....just point out you can.

 

I pretty much have the same setup for now and it is clearly not optimum! Basically, I had better performances (or at least more pleasure) before I changed the heads. The Performer (non RPM) intake was perfectly matching the stock heads and cam. Now (since the swap to Performer heads), it is not the case anymore.

My new upgrade (very soon) are going to be:

- Performer RPM intake
- Performer RPM cam

This way I will be sure to have some components that work well together

 

amen to all the above said.
The heads are sufficient (which is good), so .you'd only need to change the cam and intake. The carb is not optimum, but you might get away with that.

Edelbrock has 2 camshafts: the performer and performer rpm. The performer is a for a warmish stock 289/302, which is clearly not the case in your application.

The exact same goes for the intake.

it really is not well matched otherwise it sounds like a great engine

Kalli

 

yep, your combo will be good in a heavy truck looking for low end and MPG's. You need more cam, intake and carb. The performer cam is even mild in a 289-302

 

Thanks for the honest input that's what I need to get headed in the right direction. I took it to a nearby city Mustang shop and got nothing but vague, evasive answers. I'm not sure if this was a case of him fishing for an engine rebuild job or ?

M77 - Can you be more specific on the carb being the wrong brand?

Dodgestang - Thanks. I think I could've gotten the raw data that might've included rpm but this was my first time into a dyno shop so was a bit unprepared.

Thanks again everybody for your wisdom. I might have something decent yet.

Tom

 

what m77 meant is: "get a holley carb". That's his opinion (always has been) and a lot of people share this opion (holley or barry grant). I am just installing my first edelbrock carb ever, so I'll know the difference in the next two weeks. The holley are better tunable, but from what i heard the edelbrocks seem good out of the box.

what dodgestang is saying is 100% correct. If you know at what engine rpm that has been then you can figure shiftpoints (but i think your running c4 anyway iof I remember correctly) etc. will give you a much better picture on where it makes torque

where you pulling in 4th gear? if you let us know your tyre size (ex: 225/60R15) (we need only the rear) as well as the rear axle I should be able to calculate your engine rpm from the speed.

Kalli