60' time and 4 hole 1" spacer

[mderoy340]

I'm still fine tuning my combo and I'm going to install a 4 hole 1" spacer. Anybody seen a 60' improvement adding a spacer. I use an AFR gauge so I'll make a jet change if needed to keep my 12.8 WOT.

 

[fishy68]

Depends on a lot of things. A 4 hole will usually give you a little more bottom end, but it's really build defendant. For instance when I built my 408 I used an Eddy air gap and I tried a 4 hole and an open spacer to look for improvement and it liked the open better. That's typical with a larger cubic inch engine as they can use more plenum volume than a smaller engine.

BTW: I assume you must be using non-ethanol fuel for 12.8 to be rich enough? I can't get anything (at the pump) that doesn't have ethanol in it so it like an afr of 12.2-12.3 the best

 

[mderoy340]

Depends on a lot of things. A 4 hole will usually give you a little more bottom end, but it's really build defendant. For instance when I built my 408 I used an Eddy air gap and I tried a 4 hole and an open spacer to look for improvement and it liked the open better. That's typical with a larger cubic inch engine as they can use more plenum volume than a smaller engine.

BTW: I assume you must be using non-ethanol fuel for 12.8 to be rich enough? I can't get anything (at the pump) that doesn't have ethanol in it so it like an afr of 12.2-12.3 the best

360 Magnum, 904 low gear set, 3.91, 27" tire, 90* humid day, 12.20@109.69
I guess I'll try both and see what happens.

 

[roccodart440]

I'm still fine tuning my combo and I'm going to install a 4 hole 1" spacer. Anybody seen a 60' improvement adding a spacer. I use an AFR gauge so I'll make a jet change if needed to keep my 12.8 WOT.

Yes, use the HVH super sucker 1" spacer. It's good for 10-20hp and the same in torque.

 

[rumblefish360]

360 Magnum, 904 low gear set, 3.91, 27" tire, 90* humid day, 12.20@109.69

Nice

I guess I'll try both and see what happens.

That's the spirit!

 

[fishy68]

360 Magnum, 904 low gear set, 3.91, 27" tire, 90* humid day, 12.20@109.69
I guess I'll try both and see what happens.

Trying both is your best bet. These crazy things will surprise you sometimes and want something different than you think.

 

[MikeD]

I had a 1" phenolic 4 hole spacer which i swapped for a 2" supersucker and in back to back runs 30 mins apart i picked up .15 and 1.5 mph.
Mick

 

[mderoy340]

ran a 12.138 109.71mph with a 3/8" 2 hole. Next trip I'm going to try a 1" 4 hole.

 

[fishy68]

ran a 12.138 109.71mph with a 3/8" 2 hole. Next trip I'm going to try a 1" 4 hole.

Did you run it before you installed the spacer? If so what did it do?

 

[mderoy340]

Did you run it before you installed the spacer? If so what did it do?

This is the best I've run with it and is my baseline. It's a 2 hole phenolic heat spacer, 2400 rpm launch.

 

[elevensies]

iv just got a 2'' single hole, which im going to add to the 1'' i have (so 3''total) on a M1 hi rise air gap manifold

my guessing it will bog off the line, anyone tried this?

 

[fishy68]

iv just got a 2'' single hole, which im going to add to the 1'' i have (so 3''total) on a M1 hi rise air gap manifold

my guessing it will bog off the line, anyone tried this?

Haven't tried it but I'd guess you'd need a very large engine to use that much plenum volume. How does it do with the 2" spacer? What size engine?

 

[451Cuda]

I'm still fine tuning my combo and I'm going to install a 4 hole 1" spacer. Anybody seen a 60' improvement adding a spacer. I use an AFR gauge so I'll make a jet change if needed to keep my 12.8 WOT.

4 hole spacer is usually used as a crutch for too much plenum volume or too big a carb - improves the signal to the carb.

 

[roccodart440]

4 hole spacer is usually used as a crutch for too much plenum volume or too big a carb - improves the signal to the carb.

The HVH increases plenum volume.

 

[451Cuda]

The HVH increases plenum volume.

Right but the improved signal overcomes that increase and then some.

 

[roccodart440]

Not all 4 holes are reverse ball milled though. That was my point.

The one I posted works.

 

[451Cuda]

Not all 4 holes are reverse ball milled though. That was my point.

The one I posted works.

Tapered is the latest design and works great, but straight 4 hole spacers still have their place. All carb spacers are a tuning aid, no more.

 

[D-50394]

My pump gas small block (394 ci) made 662 hp and 533 tq with a 4 hole spacer on a Indy single plane.