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- - 598 SLUG (https://www.racingjunk.com/forums/showthread.php?t=28750)

Quote:

Originally Posted by sc4405

I'm going through this same scenario w/ a 598 right now, just won't run the MPH that it should. Biggest problem is the heads, mine has BB2Xtras CNC on it and they just won't support an engine of this CI. I'm agonizing over the Headhunters or the 3Xtra CNC right now. HH's will require new shaft rockers, intake and maybe pistons. I'm running nearly the same cam as you, and all the builders I have talked to said it's too big for the heads, but would work with better heads. You should pick up some w/ better headers, but it's still choked off with the heads. I don't have the coin for the headhunters right now but who knows later on............good luck to you! 8) JB

THANKS.. MY HEADS ARE NOT +2 CNC

I would be looking at the converter. Put a tighter one in and you will go faster. Hope this helps you

Quote:

Originally Posted by dg714

I would be looking at the converter. Put a tighter one in and you will go faster. Hope this helps you

i'd be looking at a converter also .. but no way would it be a tighter converter then he has.

Rapptor
I'd do this, go out and see if it shifts @ 7000, if it does you just about guarntee that converter is your issue @ the stripe. A 5500 nitrous converter, should be very tight, do you no the actual stall flash and fallback rpm after shift ?

Quote:

Originally Posted by dg714

I would be looking at the converter. Put a tighter one in and you will go faster. Hope this helps you

THANKS WILL TRY A NEW CONVERTOR

Quote:

Originally Posted by hammertime

Quote:

Originally Posted by dg714

I would be looking at the converter. Put a tighter one in and you will go faster. Hope this helps you

NO I DONT KNOW RPM CHANGE AT SHIFT. I THINK IT IS ABOUT 500 RPM TIRES CHIRP ..

The 141 is close (down a couple) for the ET, the 1.23 60' should be 9.30 area, but I can attribute that to the small diameter headers.

My personal opinion is the engine just isn't making the power due to some component mismatch.

Might want to find a chassis dyno before you start throwing money at it.

You need to figure out the stall of the converter. Its one of the most important things on a race car. i hate doing it this way but take 2 step chip out and put it on the transbrake somewhere and check the stall.

A less harsh way to check stall is get it going about 30 mph in high gear, let off and then mat it and see where the tach goes instantly. You can also use your playback tach or record on your delay box if it has a max RPM function. If it spins the tires, do a burn out and try again.

Old school but might still work today.

Quote:

Originally Posted by RAPPTOR23

Quote:

Originally Posted by hammertime

Quote:

Originally Posted by dg714

I would be looking at the converter. Put a tighter one in and you will go faster. Hope this helps you

NO I DONT KNOW RPM CHANGE AT SHIFT. I THINK IT IS ABOUT 500 RPM TIRES CHIRP ..

I SHIFTED THE CAR AT 7200. FELL BACK TO 6900.

Quote:

Originally Posted by RAPPTOR23

Quote:

Originally Posted by RAPPTOR23

Quote:

Originally Posted by hammertime

Quote:

Originally Posted by dg714

I would be looking at the converter. Put a tighter one in and you will go faster. Hope this helps you

NO I DONT KNOW RPM CHANGE AT SHIFT. I THINK IT IS ABOUT 500 RPM TIRES CHIRP ..

I SHIFTED THE CAR AT 7200. FELL BACK TO 6900.

well that tells ya everything IMO
it'll go 7200 at the shift with no issues, it'll do it at the finish line.
Someone missed major on that 5500 nitrous converter if the fallback is 6900. Thats very loose for that heavy car. You should look for something around 6000 fallback. You can get away with that in a light dragster/door car but not @ 3200. Typically a 5500 nitrous conv will be very tight,unless it was made for much less hp/trq to start with.