First time user of this site so I hope you guys can help. The story goes like this... I'm restoring a HQ GTS/4. She's been stripped down to the shell and re-painted. I pulled the engine out - a baby 253 and went about pulling her apart. I put new conrod bearings in but not crank bearings as I couldn't get the balancer off, put her back together and dropped her back in. I got the electrics re-installed (original wiring), got new plugs, leads, coil, battery leads, rotor and dizzy cap. I also changed over the 2 barrel strommy for a 4 barrel quady (bought that off ebay which might not be the greatest idea). Problem is that although the car starts most times- takes a few pumps of the accelorator, she runs rough and backfires out the carby. She also appears to be running rich. I've had the timing light on it and I've got her to run on the mark most of the time but the light seems to cut out rather than give a smooth shot. The mark also moves up and down and not constantly on the mark. I haven't had her tuned professionally yet as I've been trying to get rid of the backifire first. Going crazy so any ideas would help.

Thanks John,I'll need to get the numbers for the jets,the rods and the quaddy. The fuel line comes in from the side not the front. The car is a manual and i didn't block of the dizzy. The carb has a manual choke if that helps. Any idea what the ideal jet

ALSO - make sure you have a working thermostat. It makes warm up time, economy and performance improve - heaps.

John

Does the car run smoothly atall, i rebuilt a 308 and i was a tooth out on the timing for the distributor and it run ok but backfired alot


I love my 1 tonner

Your carby (7043284) is originally off a 1973 Holden V8 and is designed for a auto transmission.

hey holden fan , I think you should start from scratch, as Boswick said you should recheck dizzy initial timing ,firing order, also I think if you dont know the history of the carb it needs to be reconditioned , trubluhq has given jet/ needle details .A f

Thanks for the advise guys. Can anyone give me a name of a good carby rebuilder in south-west sydney? Cheers.

You can buy the jets you need for around $12.00 new. Just change the mains...simple. The assumption is you can disassemble and reassemble the thing. There are so many guys that cant !!

Most of the carbies I have played with via Ebay already had a kit t

If you change the primary mains should you change the rear needles as well? I presume that the main and rears are paired somehow?

cheers

Rock n Roll

Ok next question is for a 253 what is the correct size jet? I have read 67-70 odd. Can anyone narrow this down any or is that size range close enough?

thanks

Rock n Roll