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4-Barrel Intake comparison
https://www.slantsix.org/forum/viewtopic.php?t=18931		 Page 1 of 3
Author:  Bren67Cuda904 [ Mon Jul 31, 2006 10:16 am ]
Post subject:  4-Barrel Intake comparison
I ve been looking at the twin 2-barrel intake idea for two reasons.
1. Two carbs just look cooler than one.
2. Performance gains.

Costs and potentail tuning issues are leading me away from the cool factor. Performance gains can not be pushed aside. Therefor the 4-Barrel carb is under concideration. Two types I am looking at are the clifford short 4 barrel intake, the hyper pak, and the Offenshauser short 4 barrel.

http://cliffordperformance.net/Merchant ... ory_Code=M

http://cliffordperformance.net/Merchant ... ory_Code=M

I have no picture to the Offenshauser manifold.
1. Will the hyper pak manifold get in the way of added a power brake booster later?
2. Is it true that the 4 Barrel carb will likely be better than twin 2-Barrels, even considering the distrubution?
3. Isn't the smallest CFM 4-Barrel more CFM than a slant can use?
4. What are the symtoms of using a carb that is to big?
Author:  dusty7t4 [ Mon Jul 31, 2006 10:26 am ]
Post subject:  Re: 4-Barrel Intake comparison
Quote:
1. Will the hyper pak manifold get in the way of added a power brake booster later?
what vehicle do you have? early a bodies might (ask SSD) but I doubt a later model would. I am "thinking" your cuda would be safe
Quote:
2. Is it true that the 4 Barrel carb will likely be better than twin 2-Barrels, even considering the distrubution?
depending on manufacturer, size of carbs, way to many variables here. I have heard the offy is more low end (torque) where the clifford is more high end, but I have never seen a dyno sheet for it. that seems to be the going opinion. splitting them (have two 2 barrels) might give you better throttle response and better distribution. never tried it myself, I hate trying to mess with linkage and getting them in sync.

I personally love the performance gain I got with the clifford 4 barrel intake (holley 390 carb).
Quote:
3. Isn't the smallest CFM 4-Barrel more CFM than a slant can use?
No. Many people have put up to a holley 600 double pumper. depends on what your other mods are if it can handle it, and what your intentions are.
Quote:
4. What are the symtoms of using a carb that is to big?
bogging when you stand on it is the biggest obvious one I know of

-dave
Author:  Greg Ondayko [ Mon Jul 31, 2006 10:56 am ]
Post subject: 
The hyperpak will probably not work with a factory style Brake booster for the A body Barracuda such as yours.

Greg


I probably have about 1" between the master and the air cleaner housing

Greg
Author:  Guest [ Mon Jul 31, 2006 11:24 am ]
Post subject:  Re: 4-Barrel Intake comparison
Quote:
3. Isn't the smallest CFM 4-Barrel more CFM than a slant can use?
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I put a hypothetical /6 together with my cheesy old "KB Dyno" program. The most CFM it could use was 442 cfm at 6600 rpm. At this combination's HP peak of 288HP @ 6000 rpm it required 400 cfm.

The engine: 4.25 stroke/3.46 bore - 240c.i. 11/1 comp. ratio. 1.78 in. intake valve. head flow = 217 intake/160 exhaust at 28" H20 (exceptional). 316 degree (advertised) mechanical cam with .600 lift on a 106 degree LSA. In other words - a pretty stout engine.
Author:  Bren67Cuda904 [ Mon Jul 31, 2006 4:27 pm ]
Post subject: 
What is the smallest CFM major brand 4-barrel carb still in production?
Author:  panic [ Mon Jul 31, 2006 4:49 pm ]
Post subject: 
Have a nice day
Author:  Bren67Cuda904 [ Mon Jul 31, 2006 8:20 pm ]
Post subject: 
with all that said and an engine planned to be in the 240cubic range, more than mild build but not the most extreme thing you've ever heard of, what 4-Barrel carb would you recommend?
5500 max rpm
250 - 290hp
Your carb choice?
Author:  sandy in BC [ Mon Jul 31, 2006 8:40 pm ]
Post subject: 
If you are shooting for 250-290 HP there are things I would be chosing way before the carb.

I would class my build as mild at about 200hp (comp 264. big valves. chamber work, 9.25 CR) and my little BBD on a super 6 manifold does fine.

I wouldn t even bother with a 4 barrel unless I was at 10:1 CR and 280 adv duration with full porting.

It seems backwards to me to plan a build from the carb backwards. If you really make 290hp you will go through a whole slew of intake options to get there.
Author:  panic [ Mon Jul 31, 2006 8:50 pm ]
Post subject: 
If you're going to base your choice of an essential engine component on how it looks when the car is parked with the hood up I can't help you.
Author:  Bren67Cuda904 [ Tue Aug 01, 2006 5:34 am ]
Post subject: 
Is it possible to get a recommendation on a carb for a target hp range. I would think it goes with out saying that other engine work is a must to reach theses goals. Sorry it didn't want to bore you with the fine details of the build. But if you must know:
'64 225 Block .010" milled off deck surface
Milled Head .060" Old Style Head with plug tubes
Bigger Valves 1.70 Intake/1.44 ExhaustFrom Si Valves
Ported+Polished Head 5 Angle Valve Job on Intake/ 3 Angle on Exhaust
Teflon valve seals
Hardended valve seats
Mopar Performance Double roller timing chain
340 valve springs
Mopar Performance Cam .528" Lift, 284 Duration, 104 Deg. Centerline
1.6 Cox Brothers / RAS Roller Rockers Resulting in .562" Gross Lift
And last but not least- stroking the crank and using 2.2l turbo pistions.

This build was done be Greg but with out the stroking.

I think its not such a crime to be concerned about how sometime looks on a show car.

Does anyone have a carb recommendation? (except Panic)
Have a nice day :x
Author:  dusty7t4 [ Tue Aug 01, 2006 6:05 am ]
Post subject: 
I vote for the holley 390. easy to work on and plentiful. some folks round here don't like holleys though so you will hear many opinions.

inccdentally, the only mods I ever had were the 4 barrel carb, manifold and headers, no headwork or anything else.

got 25 mpg too

-dave
Author:  sandy in BC [ Tue Aug 01, 2006 6:32 am ]
Post subject: 
That build will not get you 250 HP,,,,no less 290. You cant just mill heads and block and guess what CR you will get and expect to get big HP numbers. You need to match CR and cam.

I suspect your stroking, milling and lift will make big noises.
The long rod build using 2.2 pistons makes for a zero deck style motor. What is your target CR?

Will those valve springs work with that kind of lift and 1.6 rockers?

Use the Holley 390.
Author:  panic [ Tue Aug 01, 2006 7:46 am ]
Post subject: 
What carburetor will get an almost stock 225" engine with a small cam and 4 bbl. a 100% HP increase?

The nitrous carburetor.
Author:  slantzilla [ Tue Aug 01, 2006 7:46 am ]
Post subject: 
Before you pick the carb, what trans, converter, gear will you have?

If you are gonna run a lot of gear-(3.91 or better) with a stick or loose converter I would use a 600 double pumper.

Anything less than that and I would run a 390 vacuum secondary.

I have run a 390 and Offy on an internally stock 80 Volare motor. With headers, 3000 stall, and 3.91 gears it ran incredibly well. It was actually faster than a lot of the hot rod motors that have been built. Not sure why, it just worked. :D

I have run an Offy and a Clifford on back-to-back. The Clifford lost .3 in the first 1/8th mile, and ran a little better than the Offy in the last 1/8th. I would rather have the low end with a little motor myself. :wink:
Author:  Bren67Cuda904 [ Tue Aug 01, 2006 11:00 am ]
Post subject: 
This is NOT a "Long Rod" build. This is a real stroker build. Custom welded crank.
I am sure that the milling of the head and block numbers are not right on. My machine shop will do the final calculations to get a CR that will let me to still use high octane pump gas. (91).
What I am doing here is putting together a rough plan on building a slant 255. Basicly doing lots of homework so my machine shop doesn't have to start from scratch. They build alot of inlines but not many slants. I trying to inspire ideas that they may not realize that you slanter do. Case in point- stroking the crank and whats involved. This homework should save some cost.
I realize this is going to be a pricey job and I am willing to pay. I just would like to think that I was part of the building process and not just another V8 guy that bought a proven off the shelf build.
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