Holley 450cfm on Mild Slant six

[Slantsix64]

What up slanters! I was wondering why I always see everyone recommend a Holley 390cfm or a 500 cfm edelbrock. What about a Holley 450 Cfm four barrel?

I got a 225 punched out .060, ported oversized valves, 9:1 compression. .479 lift Howard’s camshaft. Custom duals into a y pipe. With a 4 speed B&T 3.09 first.

Got a 500 cfm edelbrock, but I really like Holley’s. Is there a reason the 450cfm gets no love?

 

[Garrett Ellison]

What up slanters! I was wondering why I always see everyone recommend a Holley 390cfm or a 500 cfm edelbrock. What about a Holley 450 Cfm four barrel?

I got a 225 punched out .060, ported oversized valves, 9:1 compression. .479 lift Howard’s camshaft. Custom duals into a y pipe. With a 4 speed B&T 3.09 first.

Got a 500 cfm edelbrock, but I really like Holley’s. Is there a reason the 450cfm gets no love?

Because it's a turd of a carburetor based on a 4150 with no secondary accelerator pump. It's primarily designed for "all show" street rod tunnel ram use. I think there's a 465 vacuum secondary that would work pretty well. @RustyRatRod is using a 600 or 650 CFM (I think Quick Fuel) DP on his slant, yours would probably do well with one, too.

 

[RustyRatRod]

The only 450 Holley offers is a mechanical secondary tunnel ram carburetor and they're not designed to run as a single. I have the Quick Fuel 450 on Vixen and it runs fantastic. I couldn't ask for a better running carburetor.

 

[RustyRatRod]

This is the one I have on Vixen.

Quick Fuel SL-450-VS Quick Fuel Slayer Series Carburetors | Summit Racing

Free Shipping - Quick Fuel Slayer Series Carburetors with qualifying orders of $109. Shop Carburetors at Summit Racing.

www.summitracing.com

 

[Slantsix64]

I think the one I have been seeing is the Holley 4548 it has vacuum secondaries.
65-68 FORD 302-390-428-429 HOLLEY L-4548 MODEL 4160 CARBURETOR 4 BARREL | eBay

Looks like it came on the old 302 fords

 

[Slantsix64]

This is the one I have on Vixen.

http://[URL]https://www.summitracing.com/parts/qft-sl-450-vs

[/URL]

Damn that’s a nice looking carb

 

[Slantsix64]

@RustyRatRod how was that carb right out the box? Jet size etc. I like how it has the adjustable secondaries pod on it.

 

[Slantsix64]

I have used edelbrock for years, but since I learned how to tune a Holley carb there is no equivalent.

 

[RustyRatRod]

@RustyRatRod how was that carb right out the box? Jet size etc. I like how it has the adjustable secondaries pod on it.

It was close everywhere, except the idle mixture. I had to play around with different IFRs and idle bleeds until I got it right. Took a little while, but it was well worth it. Nothing, but nothing will be right out of the box for a slant 6 except maybe a stock one barrel or two barrel. ...and that's especially true for a non stock slant 6. So if you don't want to tune, build a stock motor. lol

 

[Slantsix64]

It was close everywhere, except the idle mixture. I had to play around with different IFRs and idle bleeds until I got it right. Took a little while, but it was well worth it. Nothing, but nothing will be right out of the box for a slant 6 except maybe a stock one barrel or two barrel. ...and that's especially true for a non stock slant 6. So if you don't want to tune, build a stock motor. lol

Lol imma tune regardless! Maybe I’ll just save up for the quick fuel 450.

 

[RustyRatRod]

Lol imma tune regardless! Maybe I’ll just save up for the quick fuel 450.

I tried Quick Fuel's version of the 650 DP on Vixen not too long ago. It actually ran great but the low speed operation was too rich and I didn't spend as much time on it as I did the 450. The 450 ran so good I put it back on. It's just flawless. The 650 was too......everywhere but idle and "a hair" above.