_Kal05_
Posted 09 May 2013 - 04:04 PM
Hi all,
am have trouble tuning my quadrajet carb, its on a mild 253.
always seems to run rich.
Does anybody know of someone in nth qld who is good at tuning these and has experience??
also is the quaddy best for a 253? or would the smaller holleys be better for performance?? (ie 350, 390 or 465)
im not really worried about fuel consumption. more so looking for best performance.
Cheers
Oh My, Don't you post alot
Posted 09 May 2013 - 04:13 PM
Cairns..... Your screwed mate. Sorry.
_Kal05_
Posted 10 May 2013 - 07:42 AM
awesome.. haha
would any of the holley's be a better option for the 253??
im running 30 thou flat tops, L34 heads and mild cam, looking for best performance.
any ideas??
Oh My, Don't you post alot
Posted 10 May 2013 - 07:57 AM
The problem is mate, there are no competent mechanics in Cairns capable of tuning/jetting cars with carbys. The shops that are around with dyno's only play with EFI/Diesel.
Cairns Dyno Tune may have been an option but they ran an ad in the paper a year or so ago advising everyone they no longer service Carby's.
_Kal05_
Posted 10 May 2013 - 08:52 AM
yeah i understand that.
im just starting to wonder if a quaddy is the best option..
i am after peoples opinions and experience on here as to what the best carb has been from their experience on 253's
Fulcrum Fixture
Posted 10 May 2013 - 12:34 PM
My experiences are standard ported heads, mild cam, edlebrock performer, 465 holley, flat tops = performance.
With L34 heads I'm not sure but you may need a bigger cam to bump up the redline and go a rochester or 600 holley.
You may also get bore shrouding of the valves and on high lift maybe even contact.
Exactly what manifold are you using?
_Kal05_
Posted 10 May 2013 - 01:21 PM
im running edlebrock performer manifold, the bores have been scolloped to take the bigger heads, cam is slightly bigger then standard, not sure on exact size though,
i originally had an old 465 holley which come with the motor but i didnt like it, never seem to give good performance, (may have not been the best condition), i changed to a quaddie that was set up for a standard 253
which is ok but does really give me anything down low, im really just after the best for performance, i dont care how much fuel it drinks as work pays for my fuel haha.
would a 600 double pumper be too much??
set up
253
30 thou flat tops
mild cam
performer manifold
t5 manual
Fulcrum Fixture
Posted 10 May 2013 - 01:32 PM
Those heads and small cam would probably hurt low end torque and Vacuum (read as ignition timing and air speed) if not matched to the CR.
As to the above, if either carby you used did not perform then they (including ignition timing) were either way out of tune, needed a service or were not correctly set up, they would give you the best punch.
Also to consider, if you have a poor/weak ignition system you will never get it to pull away at low speed, it will pig root and want to change back a gear.
Edited by TerrA LX, 10 May 2013 - 01:34 PM.
_Kal05_
Posted 10 May 2013 - 02:06 PM
you may be right terra, the carbies may not have been correctly set up,(although i bought the quaddie of Hume and it was set for a 253) i know the timing is good.
im running electronic dizzy with 50k volt coil (good leads and plugs) so i dont think that would be the issue
could be the bigger heads knocking some torque out.
i dont know enough about quaddies to go playing around with it but it always seems to run rich, i would like to try the 465 street avenger and set that up properly
to see if it makes a difference as i think the holley would be easier to tune for someone like myself
_ATD350_
Posted 27 May 2013 - 03:36 PM
demon used to make 525 street dem. that would be ideal. Essentially same as a 600dp, just a little smaller in the venturies.
Honestly though, low end performance and L34 valves just dont work, even on 308s and larger. big valves for big engines.
its a big commitment i know, but I have $5 say that your quadrajet and performer and cam, would make 1-20 more hp and 20-30 more foot pounds everywhere, with a set of bowl ported standard valve heads, milled to give at least 10.7:1 comp.
Potentially still cheaper than a new holley and a day on the dyno.
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