5.0 Slugish after rebuild??

[fatty1]

I recently rebuilt my 5.0 back to stock just new rings and bearings heads done etc...the car was already running on gas and it used to pull up to about 5500, after the rebuild it will pull to about 4000 then just get loud and not pull any harder???
The timming has been set but it seems like the engine is starving, I can't confirm this due to it not running on petrol
Any ideas??

[greenfoam]

Well you would have to say it's either, wrong ignition timing, cam timing, not enough fuel or a block cat

[fatty1]

The cat is free flowing ie the insides have been removed the ignition timming was done quickley just with a timming light thats why I thought it might be fuel??

[fatty1]

Oh forgot to add I also thought it may have had a v6 memcal but when I checked the numbers on the chip to an earlier post I saw it was a stock vn v8 tune

[greenfoam]

Did you do the timing in diagnostic mode?

[ari666]

so the rings are new? and your already revving to 4k rpm?

[Darren_L]

are you sure you got the cam timing right ?

[fatty1]

so the rings are new? and your already revving to 4k rpm?

Car has done around 2k or so to loosen it up was run inn for a bit

The timming may not have been done in diagnostic mode the mech who did hard stuff ( timming chain, dizzy and cam ) did the timming so it may still be out

Prettys sure the cam timming is right or it wouldn't idle properly would it??

[greenfoam]

90% chance the ignition timing is wrong then if a mechanic did it, they aren't the best at this kind of thing but it would have to be very far out to not go over 4000 rpm

[fatty1]

It may go over 4k but doesn't pull and sounds like its screaming

[chargedvx6]

Cam or ignition timing for sure. I got my cam timing wrong when I fitted a double row and had the same problem. I was 4 degrees too far advanced and the thing just would not rev up and you had to hold the throttle for a couple of seconds to just get some revs in N.

I's back to dot to dot now and is great

[fatty1]

Ok an additional developement is ...... when I bounce on the throttle ie throttle on and of rapidley I blow my airbox up is this just a backfire through the thottle body
Also why will a v6 memcal run my v8 is it because the 8 is on gas only??
The memcal I have is a AFTY one with a white chip on the board with 1H9327 what is it???
Thanks

[greenfoam]

Thats a v6 memcal and that's not ideal at all :P, why exactly are you running a 5 litre with a V6 memcal

[fatty1]

I am not it was just a spare computer and memcal I had lying around, I was told I could use it just to test
What is the white board attatched next to the memcal?? is it a knock board??
Cheers