Need some advice, almost ready to start up my new motor( combo in sig) on the Dyno ..... would like to try a 1" carb spacer ... anyone have an opinion on which style might work best ...I have a 1" 4 hole and a 1" open I can borrow but was considering getting one from HVH www.highvelocityheads.com (http://www.highvelocityheads.com)
PN ST 4150 "StreetSweepr" for 4150 series dual plane intakes ...Performer RPM.....have 3 Holley carbs to try
750 vac secoundary , 950 3 barrel vac sec. and 950HP still jetted out of the box



From what I have seen on motors similar to mine for street strip cars 2" usually not the way to go and open 1" rarely makes as much torque as a 4 hole but I realize every motor different.
This HVH 4 hole to open style looks like it has merit...anyone got an opinion ??

Thanks Bill

Bill, I haven't done enough different engine combos to even have general guidelines for expected spacer results. The only thing I can say for sure is that on centrifugal blow through carb engines a spacer is needed to keep the air cloumn moving in the proper direction.

For sure each engine is different. I think it all comes down to the plenum volume needs of a particular engine. If the engine in question does not have enough plenum volume, then a spacer will make power. I also like the idea behind the sculpted spacers that can decrease turbulance.

Good luck, I think you have way too many things planned for your dyno tests (this coming from a guy who has done as many as 39 dyno pulls on the same engine before getting it right!).

Thomas

Thanks for the info Thomas ..your pbly right I am trying to do too many things , have a 4 hour session booked primary function is just to start it up and ensure no leaks and no "issues" I really don't expect a need to play with anything except carbs and spacers :rolleyes: this is not the session to get the max out of it just get a good basic combo figured out before it goes in chassis. Note I said chassis....body still in paint jail graemlins/boring.gif Bill

HI Bill,
Good to hear your project is rollin along graemlins/thumbsup.gif

I think Thomas is petty much spot on with the spacer deal.
On a 489 with a Vic Jr it liked an open spacer.
Picked up around 10-12HP, peak torque didn't really change.
A four hole spacer didn't do anything.
I also agree a spacer tends to do two things,, one it creates more plenum volume & two it helps to turn the mixture.

On a 383 with a Perf Air gap it also liked the open spacer but seemed to lose just a little torque & a small HP gain.
Probably made the thing more like a semi single plane.??
What I have found is it is really something you need to try, kinda like timing, some engines are very picky & will lose a bunch with a 2 or 3 degree change & others will make the same power over a 6-8 degree spread.
The HVH spacer really worked good on an 18 degree head 390 carb 355 we tried it on.
About 20HP but this is a restricted deal so I don't think you can count it.
We tried it on the guys open 406 & it didn't seem to care much for it but it had a GM Bow Tie that was a real good intake done by HRD as were the heads & a Braswell carb that was also real nice.

OK I understand what you guys are saying with regard to spacers ...
Thomas is the HVH spacer the type that you consider a " sculptured spacer" to decrease turbulence ???? I call it a spacer with an inverted turtle ?? anyway trying to get an idea if I should buy one to try or just try the open and or the regular 4 hole.

Wilson Manifolds makes some really nice spacers (and manifolds too):

http://www.wilsonmanifolds.com/

I'm running one of their tapared spacers. It's like a hybrid open/4-hole spacer combo and works similar to the HVH. These spacers provide the low-mid range torque benefits of a 4-hole spacer and the added benefit of smoothing the transition the air/fuel has to make as it enters the runners. In theory this helps to keep the mixture up. Works for me smile.gif

At my 540 dyno session, we were able to try numerous spacer combos. It was one of the items I wanted to focus on. All were 4500 series spacers.
First tried none, then 1/2" open, then 1/2" 4 hole, then both stacked together, and finally the 1" HTH with the 4 hole to open configuration.
The best setup for my engine was the 1" HTH super sucker.
This was on a port matched Super Victor with a 1050 Dominator.
And truthfully, there wasn't a 10 hp max difference between the worst and the best.

Thanks for the info Ken, I was wondering if you would see the post .... Wilson is very nice stuff..I didn't know they offered that type of spacer as well. Thanks , I think I will buy one of these "hybrid" 4 holers and see what happens ....although just was test fitting my 35yr old headers ( which are excellent ) and the pass side one hits the Canton pan kick out graemlins/sad.gif
Thank god I had not cut them up to install the Flowmaster Merge collectors I bot .... every item from the old combo that I thought I would use to save some cash will now have been replaced :D so much for the budget Day 2 resto !