I'm starting the planning stages of my 250 turbo build. I will have a ton of questions, but for now...
What is the better intake for the turbo? Offenhauser or Clifford? Or maybe something else?
I currently have a holley 390, clifford headers, and offenhauser intake. Im selling those but not sure to keep the offy or not.
I may end up fuel injected also. Any intakes on the market for that?
Thanks.

also here is my build page for more info.
http://67-72chevytrucks.com/vboard/showthread.php?t=257202

What is the better intake for the turbo

Better to do what?

I would venture a guess the question is does one or the other work better with a turbo Tlowe can probably give the best answer there. But as far as installation or adapting pieces both intakes are pretty close to the same, now as far as fuel injection, do you want to go throttle body or port injection? Haltech has an intesting kit that can be used for port injection. http://www.haltech.com

I prefer the Clifford intake. It also will be alittle farther from the exhaust heat.

There is a intake for EFI that I offer. It is made for multiport injection, like I do. They are instock.
Tom

[quote=tlowe #1716]I prefer the Clifford intake. It also will be alittle farther from the exhaust heat.

There is a intake for EFI that I offer. It is made for multiport injection, like I do. They are instock.
Tom [/quote
I'm interested? Is it cast as an EFI or do you add bungs?

Thanks.
Tom, do you have a link or any pictures of that intake? I've seen one manufactured in Australia that is mpfi and uses lsx parts. Is yours similar?

work better with a turbo

The smaller plenum will pressurize faster, but may be down slightly on maximum power.
I prefer the Clifford runner shape, but not very happy with either one.

I'm tempted to build my own. I've seen the flanges on ebay so It wouldn't be very difficult. For simplicity I'll most likely go with the clifford and a 500-600cfm carb but I'm interested in the mpfi now too.

The one I have is cast and the bungs are machined into it. Tom

I think the newer clifford intakes have a pad at the port and you can drill and tap for injection.

OK. I'll have to check with them.
These engines are real popular in South America, It'd be nice to find one of their aftermarket companies for parts..

I have read that a larger plenum intake, which would be the clifford in this case, is better for a turbo engine. I have no dyno time to confirm this. I think with smaller engines, a plenum with a volume approximately 1.5x engine displacement helps with power. I don't know if at the power levels or engine displacements we are talking about here that this is required or desired. I personally am running the clifford.

I see that mostly clifford has been recommended for this turbo setup. So why did you guys recommend the offy for my turbo build?

I prefer the Clifford.

Not sure exactly who recomended the Offy.

The Offy will work fine, but will limit the airflow at higher rpms and boost. Lets say 10 PSI and 4000 RPM it will start to be a bottle neck. Tom

No commercial manifold is anywhere near 150% of engine volume. Assuming the manifold length is 24" (Santucci), that's a 4-1/2" cylinder or 4" box.

Kyull,

I think you sold the Offy & got a Clifford?
I think the Offy will distribute the A/F better that the Clifford manifold because of the squared off corners.
I believe you are going to blow through a carb?

Plus I believe the Offy will build boost quicker & give you better throttle response. Also better overall drivability.

With the Offy being smaller ports over the Clifford, being you are forcing air/fuel through it, the smaller runners will not be really restrictive as some think it would be.

W/the Clifford, numbers 1 & 6 will get more fuel & 2 & 5 will run lean.

If you are going to use the Clifford intake I would run a devider in the ports to get closer to equal A/F delivery.



To get even better distribution, you would need to make a devider in the cyl head, but that drastically kills the airflow & would require to make your intake port windows a lot bigger to gain some of the lost airflow back.


MBHD

Thanks for the reply. I think since my turbo is on the smaller side I may be ok with the clifford building boost.

I have no problem building boost with mine, also have a Clifford.

Having 292+ CI engine helps when using the Clifford.

MBHD