Valtech Jet Blocks for Holley carbs

I've been looking at these http://www.jetblocks.com for a 390 Holley on my 225 V6.

Anyone try these out for fuel control when running extreme angles and camber? Trying to figure if I should spend a few dollars on them.

 

Wow, thanks for posting that! I've been working on Holleys since the mid 80's (worked many years in a speed shop that was a Holley warehouse distributor) and I thought I'd "seen it all" but that's a new one on me.
The re-location of the fuel pickup isn't a huge change, but it might be enough to make a difference.
They aren't expensive-I say give it a shot & see what happens! I may try one myself.

 

Looks like they should help. But I have not tried them.

They don't solve every problem identified with the Holley though. They do not prevent gas from coming out of the bowl vents or the vent slot at the top of the bowl. And they don't dampen float bounce.

I would give them a try ... but I would also raise the bowl vents, add a vent whistle or slosh screen, and spring-dampened needle/seats. I wonder whether, after all these extra parts, you end up at a lower cost than a new TA. The 470 TA is not that far off from the 390 CFM carb, and should be ok for a 225 ... I'd think. The TA also features annular boosters which the 390 does not have ... so I would think that low speed performance would be roughly equal to the 390 (high vacuum signal is why you want a smaller carb). Are any members running the 470 TA? The other possibility is to find a used 390 on eBay or wherever, and rebuild/modify as above.

<edit> Never mind - the 470 does not come with annular boosters. Still might be ok. And it is possible to fit new boosters, if they are available as a speed part.

 

I'm running a TA470 on a Dauntless.
Works great off road (I think that thing would run upside down!) and has good power, but it has part throttle driveability issues I haven't been able to eliminate.
I wonder if the 390 CFM carb with this kit in it, along with spring loaded needle/seats and bowl vent extensions, might be better...

 

Hmmm. I have an Offy 360 Dual Port manifold, which I think will provide a high vacuum signal and fair to high velocity. So I have even thought that I might need some additional restriction, but don't know yet. Also have headers and some porting done on the head.

Tim, I plan on all the usual mods for off road, but it seems that the Valtech Jet Blocks would work better than jet extensions on a bowl with a side hung float.

I am thinking that I would set this carb up with two metering blocks with Valtech blocks, needle valves with spring seats, vent extensions, and fiddle with the jets and accelerator pump cams to overcome the stumble that could come from vacuum drop/leanout off idle. I didn't know that the boosters on a 4160 could be replaced. Annular boosters would probably help with fuel atomization and help it burn a little more efficiently.

What about a spacer or isolator under the carb? Any benefit?

 

Don't use a thick spacer, that has the effect of raising your RPM range.
I like to rum a 1/4" thick heat insulator type gasket to help isolate the carb from engine heat, although that's less ofor a conicer on an aluminum manifold.

 

Thanks, Doug. Forgot to add that this engine has a high lift, short duration cam. Obviously trying to make max torque on the low end.

 

wow pretty cool ,I might just ditch my 2G for my old 390 ......

 

Huh. Jet extensions. I had forgotten about that one.

As I recall, they are short pieces of thin-wall brass tube from the hobby shop, soldered into the jets.

 

Those are pretty cool! I bookmarked that page.

 

Better yet , Fuel resistant Plastic tube that just snapped over the Jets.........

 

The Valtech jet blocks would negate the use of jet extensions. Still would add a vent whistle.

 

so,,this got me thinking ,SWAY is a real dog with weight and 35's ,so I unbolted my 2G dusted off my 390 that was stitting for 15 yrs and bolted it down to my Offy 360 ,filled the primary bowl and pushed the button ,,,vroom ,started right up .accel pump is crunchy but runs very smooth ,MUCH smoother than my 2G. I used it one time in the Glamis dunes and the dauntless really spun up with the bigger carb . the 2G is like a rev limiter but the Holley didn't like rocks. this is way before spring loaded seats and my knowledge of carbs . I'm going to fiddle with this cute tiny holley for a while ,but I'll need gaskets, spring loaded seats , rig up pig tail vents,and new throttle linkage .maybe order this setup ..... THANKS I'll give this a try .

 

Thanks Chuck
might take you up on that, after I finish my front axle project!

 

a normal 390 only has 1 metering block so you only need 1 from Valtech

 

Yes, I know. I was thinking to add a secondary metering block. Holley has a kit for not much money. That and the extended venting, spring loaded valves and vent whistles is all I plan on right now. Am I thinking correctly here?

 

I'm running a Holley 2300 on my 225 v6. So far, it runs great. With 350 CFM, no stumble. I want to try the Valtech Jet Blocks. Just for added insurance, if I try a steep climb. Have not had any fuel problems even with my center hung bowl. But, never say never! Thanks for the info. On this product! Vance.

 

why would you add the block and not just use the plate it comes with ?

 

The metering plate doesn't have removable jets.