466 pump gas street engine HP/Torque results

Looking for opinions, are the results about what they should be, or if it should be better, any recommendations?

Car:71 Mustang Conv, street car, guessing weight based on specs @ 3750, plus fluids and driver.

Engine: 466 d0ve block, 460crank, cj rods stock 460 pistons fly cut for 2.25 valves, iron CJ heads, thermactor bosses removed, Lunati voodoo hyd flat tappet 233/241, 564/582,110/106, edlebrock performer rpm(7166), pro systems carb 950 main body, 2" headers into 2.5 exhaust to the mufflers, 3" tailpipes,

Chassis Dyno results: peak HP 378.65@5500, torque 447@3600. with accessories = power steering, alternator, water pump, 4spd trans, 3.5 geared 9in traction lock.

torque at the start of the pull (2200rpm) was 380 and went over 400 @ 2800 rpm. It started dropping below 400 @ 4900 rpm.
hp at the start was 150 went over 300 @3500 and started to drop off after it's peak @ 5500

The torque seems good, pretty flat across the rpm range but the hp seems to be lacking, only increasing 78 hp from 3500 to 5500.

Staci

Exhaust duration not enough......exhaust port needs more time to get the exhaust out. Engine is smothering.

I am glad you responded, I know you are one of the experts on this site. If you were to design a cam for me, what should I expect to see for a gain hp/torque? Also, since this is a street car, would you recommend staying with a hyd flat tappet or what do you think? I have enough clearance to go up to .620 lift with the right springs.

69BOSS wrote:I am glad you responded, I know you are one of the experts on this site. If you were to design a cam for me, what should I expect to see for a gain hp/torque? Also, since this is a street car, would you recommend staying with a hyd flat tappet or what do you think? I have enough clearance to go up to .620 lift with the right springs.

I'm no expert. Just happens this is my chosen profession. I'd say there is an easy 75HP to be picked up. That cam really has a cork in this one's pipe.

I would say 75hp is significant. If you say it's easy, maybe there's even more to be had. We need to talk!

Curious to see what the recommended cam is.

SandHillsHillbilly wrote:Curious to see what the recommended cam is.

I've already done a flat tappet change for eddy headed engine and the customer was VERY happy:

https://www.429-460.com/t23312-cam-change-what-to-expect?highlight=Hyd+flat+tappet+cam+change

WHY is that 2 1/2" section in the exhaust system ...?
Make it 3" all the way through and put as large a crossover pipe as will fit between the two, (a 4" pipe with the ends ovaled), after about 68 inches total length from the farthest head port.

2.5" pipes because it's a convertible and there is floor brace under the car. The current pipes run between the brace and inside the tunnel area. There is not enough room to increase the size. If I ran the pipes under the brace, there won't be enough ground clearance. A 4" pipe would leave less than 2" of ground clearance. If this were a hardtop, it wouldn't be a problem.

69BOSS wrote:2.5" pipes because it's a convertible and there is floor brace under the car. The current pipes run between the brace and inside the tunnel area. There is not enough room to increase the size. If I ran the pipes under the brace, there won't be enough ground clearance. A 4" pipe would leave less than 2" of ground clearance. If this were a hardtop, it wouldn't be a problem.

A 4" pipe SQUEEZED to 2 1/2 inches thick is an oval; same with a 3" pipe.

If it was easy, you wouldn't be here asking for help.

I said 4" pipe, I meant to say 3". Anyway, with 2.5" in the tunnel area there is very little clearance. I would have to get a section of pipe and check to see if 3" could fit. If it would fit, I am all for it. I guess I could look into making a modified brace that would allow the pipes to hang a little lower. It's never easy.