Dissapointing performance

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Dusterguy

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I bought IMMS rhs heads to my 360 and after swap I didnt see any performance gain. My old heads were badly ported 596 heads with 2.02 inch valves. They had clearly too small pocket porting area compared to valve thats why I thought that they are badly ported.

I tried 35 and 33 ignition advance and I didnt see difference. Car can hardly do a burnout. I did try 1/8 mile run after and before head swap and I gained 1.8 miles per hour trap speed! It was 85 with these new RHS heads. Putting weight and that speed in calculator I got 305 horsepower. Thats nothing I feel I should have more like 400hp than 300. I am very badly dissapointed to these heads. Can anyone quess what is wrong in this engine?

Here is my combo

360 0.040 oversize
Kb107 pistons
10:1 compression ratio (yes I measured it)
piston to head distange about 0.078 inch
Comp cams mechanical flat tapped 282 degree cam in advertised duration 240 in 0.050 lift. LSA 110 ( I did degree cam it is right )
RPM intake
600 edelbrock vacuum secondaries
1 5/8 shorty headers
2" dual exhaust (might be little small but not that small?)

20 decree idle ignition advance and 35 total. Car runs and feel right but only doesnt have power more than it has.
 
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3.23 rear end ratio
904 lockup trans and 2200 stall speed custom converter. I havent found bigger stall speed converter here where I live.
14 inch wheels not so tall tires 205/50
 
600 is a bit on the small size carb, 670-750 vac secondary would be better. 2.5" dual will help that motor breath.
 
What do you feel what is correct full rpm ignition advance for magnum type head?
 
Poorly carbureted and even more poorly exhausted. Cam is also a little big, IMO. As asked, what gears and converter? So far, looks like a bunch of mismatched crap. Except the heads.
 
That thing should be frying the tires. Sounds like you need some carb tuning or just try a different style and size to see if that is your choke point. You could probably eek out a few more degrees total timing but there is more to it that timing. Vacuum at idle? How do the plugs look?
 
Poorly carbureted and even more poorly exhausted. Cam is also a little big, IMO. As asked, what gears and converter? So far, looks like a bunch of mismatched crap. Except the heads.
Not any carb will ad 100 hp in it. or exhaust. Cam too big?? These heads support over 500 hp in theory. Are you joking I think this combo is good matched.
 
Not any carb will ad 100 hp in it. or exhaust. Cam too big?? These heads support over 500 hp in theory. Are you joking I think this combo is good matched.

With that reply you lost me. What are you saying here? If you like the combo why ask for help? Am I not seeing something here?
 
Not any carb will ad 100 hp in it. or exhaust. Cam too big?? These heads support over 500 hp in theory. Are you joking I think this combo is good matched.

So, you think a 360 with a 600 carb, 2" exhaust, heads capable of 500 HP with a 2200 (stock) converter and 3.23 gears is "good matched"?

Then why are you here complaining about power output?
 
With that reply you lost me. What are you saying here? If you like the combo why ask for help? Am I not seeing something here?
I like my combo but something is wrong. I know its not wxhaust or carb even they are not perfect for this. Like I said this motor should make 100hp more.
 
So, you think a 360 with a 600 carb, 2" exhaust, heads capable of 500 HP with a 2200 (stock) converter and 3.23 gears is "good matched"?

Then why are you here complaining about power output?
If the car cant even make burnout it cant be carb or exhaust. It was making burnout with old heads.
 
That thing should be frying the tires. Sounds like you need some carb tuning or just try a different style and size to see if that is your choke point. You could probably eek out a few more degrees total timing but there is more to it that timing. Vacuum at idle? How do the plugs look?
vacuum was 20 but I dont remeber what scale it was. Havent look plugs yet I use magnum stock plugs rc12yc
 
I agree with these other guys, you have a converter that locks up before the engine begins making any real power coupled with a 3.23 killing the power down low. Heads and cam that breathe choked by a 600cfm and tight exhaust.
 
And gears or converter doesnt change engine power. Like I said 1/8 mile speed tells that car has no power more than before. Something isnt right.
 
What is you vacuum reading at WOT bet it's high. Indicating you need a larger carb, Torque converters are all about torque multiplication and if it stalls early you get NONE. 2200 is pretty much a stock converter. Exhaust back pressure can absolutely kill output.
 
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Actually I have lockup function blocked it is not working. Even if my converted is not good would it affect 1/8 mile trap speed? I dont think it would. I had same converted before swap.
 
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