TQ guys - sec jet mod
- Thread starter ratbastad
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I’m not sure but 1/4-28 is a standard size. 1/4-32 is not as as far as I know. I’ve never seen or heard of a 1/4-32 tap.
Take a piece of scrap steel, 1/4 inch thick will do and drill #3 hole and tap 1/4-28. See if the jet screws in.
Take a piece of scrap steel, 1/4 inch thick will do and drill #3 hole and tap 1/4-28. See if the jet screws in.
From Holley themselves.
https://www.holley.com/products/fue...mponents/jets_metering_rods_bleeds/main_jets/
I’ll be dipped, going to have to look this up in machinery’s handbook. If you can even find a 1/4-32 tap,I imagine it won’t be cheap.
Anyway, mind sharing the source of these TQ mods?
Rat,
Haven't seen those mods before. What DOES work & is much easier is the sec mods under my name in Oct 23. PM if you want more info.
How good is it? 3900 lb [ without driver ] Pontiac 455, 3.31 axle T400, 850 Chrys TQ ran 11.7/119, 11.6/118, 11.5/117 mph at Eastern creek. Inexperienced driver & NO tuning done at the track. 850 rpm idle, factory power brakes.
Haven't seen those mods before. What DOES work & is much easier is the sec mods under my name in Oct 23. PM if you want more info.
How good is it? 3900 lb [ without driver ] Pontiac 455, 3.31 axle T400, 850 Chrys TQ ran 11.7/119, 11.6/118, 11.5/117 mph at Eastern creek. Inexperienced driver & NO tuning done at the track. 850 rpm idle, factory power brakes.
It's 1/4 32. I JUST tapped a main oil passage plug in a slant 6 to accept a Holley main jet.
Bewy I saw that post mate (good stuff) and have done that mod on another 800 TQ. Great number in the obese Injun too haha.
I think this SEC / Holley jet mod is done by the Super Stock guys. The mod the rear jet and emulsion tube / Hi speed air bleed to suit and also retap the PRI jet thread to Holley size to run the Holley jets.
On the PRI side after the jet mod they also lose the metering rods and tree and jet accordingly.
I'm surprised no one has tried this mod - guess I'm gonna be the lab rat to give it a crack haha.
I think this SEC / Holley jet mod is done by the Super Stock guys. The mod the rear jet and emulsion tube / Hi speed air bleed to suit and also retap the PRI jet thread to Holley size to run the Holley jets.
On the PRI side after the jet mod they also lose the metering rods and tree and jet accordingly.
I'm surprised no one has tried this mod - guess I'm gonna be the lab rat to give it a crack haha.
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You should document the progress of your modification experience and post it here on FABO. Alot of TQ fans here.
Well the jet mods have been done.
Very easy and AFRs in the mid 12s at WOT. Note the Holley jet #s to actual orifice sizing t to enable comparison to TQ sec jet orifices.
Finding a 1/4-32 tap was a snap.
The Sec spray bars were modded as well.
Very easy and AFRs in the mid 12s at WOT. Note the Holley jet #s to actual orifice sizing t to enable comparison to TQ sec jet orifices.
Finding a 1/4-32 tap was a snap.
The Sec spray bars were modded as well.
Hey Bewy driven it yes.
The engine is a 283 SBC, hyd FT cam with ported power packs in an OT light hot rod with a 5 speed and 3.9 rear. Will likely be around 285HP max. No reason you could'nt use it on a 273 or 318 either.
The car drives great, has great throttle response and great on the fuel with the foot out of it.
It's an 800 cfm TQ, so more than enough carb for what I'm doing with it.
The jet mod is easy and eliminates the issue with sourcing/modding TQ Sec jets, enabling the TQ to be jetted correctly on smaller CI street engines at WOT.
The engine is a 283 SBC, hyd FT cam with ported power packs in an OT light hot rod with a 5 speed and 3.9 rear. Will likely be around 285HP max. No reason you could'nt use it on a 273 or 318 either.
The car drives great, has great throttle response and great on the fuel with the foot out of it.
It's an 800 cfm TQ, so more than enough carb for what I'm doing with it.
The jet mod is easy and eliminates the issue with sourcing/modding TQ Sec jets, enabling the TQ to be jetted correctly on smaller CI street engines at WOT.
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I’m late to the party and I’m guessing you figured it out.
My answer is yes. Once tapped, the Holley jet works well.
My answer is yes. Once tapped, the Holley jet works well.
Also, how did you handle the seals in the main jet wells? Seems the slots in the jets would leak. And did you cut the stock jets down the length of the holley jets? Lots of details left out.
Rusty - the measurements as to shortening the TQ jet and air bleed/emulsion tube are in the OP. I'm not sure what seals you're referring to for Sec jets, the TQ O rings are on the Pri side no ?
Bewy atm I have # 85 Holley jets or about a .100" orifice, stock 318s ran around .110".
Bewy atm I have # 85 Holley jets or about a .100" orifice, stock 318s ran around .110".
Oh ok. I missed it. And yeah, you're right. It's been too long since I tore into one.
SO the way I read this is, after the mod, you have replaceable jets primary and secondary, right?
I'm using OE TQ jets /rods on the Pri side as I have a good stash of those, Sec side I'm using the Holley jets.
No need to mod the Pri side for Holley jets due to jets /rods I have already have available.
No need to mod the Pri side for Holley jets due to jets /rods I have already have available.
FWIW - To those that don’t know…
The Holley Jet mod on the primary side is possible, but with the exception of the glued on factory fuel well below it doesn’t allow for an EZ conversion. If the TQ being used already has the wells already fallen off, then I’d do it. But not if it’s still intacted since breaking it is tooooo dang easy. No replacement parts available for that.
The Holley Jet mod on the primary side is possible, but with the exception of the glued on factory fuel well below it doesn’t allow for an EZ conversion. If the TQ being used already has the wells already fallen off, then I’d do it. But not if it’s still intacted since breaking it is tooooo dang easy. No replacement parts available for that.
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