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-   -   Intake & Carb Recommendation for 481" BBC (https://classracer.com/classforum/showthread.php?t=19342)

Michael Pliska 07-29-2009 10:43 AM

Intake & Carb Recommendation for 481" BBC
 
I'm running a 481" BBC, with a 0.714" lift, 292°/292° duration cam, Patriot Performance match-ported 320cc heads (2.300/1.880 valves). I'm currently running the stock 850 Holley and Holley Strip Dominator from my old iron-head motor, but figure that I'm under-carbureted for this combination. I've noticed when running against similar speed cars (5.90's in 1/8 mile) I can 60' and 330' quicker, but they start pulling away in the top end, and it will only be worse in the 1/4 mile.

Any recommendations for a cost effective carb & intake to pick up a little HP?

Regards,

jmarkaudio 07-29-2009 02:17 PM

Re: Intake & Carb Recommendation for 481" BBC
 
The 454R seems to be a popular BBC intake, Edelbrock makes quality products. For a carb, a Holley Dominator 7320 HP 1150 would be my choice. It should be real close with only jet changes that your engine may need.

Duane Dagostino 07-29-2009 02:31 PM

Re: Intake & Carb Recommendation for 481" BBC
 
I have a 1050 Nickerson stage 5 and an adapter to use it on your manifod...let me know if your interested...$750

Floyd Staggs 07-29-2009 04:35 PM

Re: Intake & Carb Recommendation for 481" BBC
 
I run a Merlin X and 1150 Dominator on my 540.

Ron Finney 07-29-2009 09:21 PM

Re: Intake & Carb Recommendation for 481" BBC
 
When I switched from my 850 to a 1050 on my 461" iron headed BBC, I gained 3 tenths. I still run the 1050 on my Dart 325 headed 496 with a Dart intake and it works great. The Edelbrock Super Victor also worked well on the 496.


Ron
33 S/C

Tom Goldman 07-30-2009 04:10 PM

Re: Intake & Carb Recommendation for 481" BBC
 
Quote:

Originally Posted by Michael Pliska (Post 132271)
I'm running a 481" BBC, with a 0.714" lift, 292°/292° duration cam, Patriot Performance match-ported 320cc heads (2.300/1.880 valves). I'm currently running the stock 850 Holley and Holley Strip Dominator from my old iron-head motor, but figure that I'm under-carbureted for this combination. I've noticed when running against similar speed cars (5.90's in 1/8 mile) I can 60' and 330' quicker, but they start pulling away in the top end, and it will only be worse in the 1/4 mile.

Any recommendations for a cost effective carb & intake to pick up a little HP?

Regards,

Tried almost every manifold out there over the years. ....Hard to beat the Edelebrock 454R on a 4" stroke motor under 500" .....My old "out of box" 8896 has been better than any of the"Pro" carbs I've run on smaller motors. ..........Tom

Tim H 07-30-2009 06:36 PM

Re: Intake & Carb Recommendation for 481" BBC
 
Quote:

Originally Posted by Michael Pliska (Post 132271)
I'm running a 481" BBC, with a 0.714" lift, 292°/292° duration cam, Patriot Performance match-ported 320cc heads (2.300/1.880 valves). I'm currently running the stock 850 Holley and Holley Strip Dominator from my old iron-head motor, but figure that I'm under-carbureted for this combination. I've noticed when running against similar speed cars (5.90's in 1/8 mile) I can 60' and 330' quicker, but they start pulling away in the top end, and it will only be worse in the 1/4 mile.

Any recommendations for a cost effective carb & intake to pick up a little HP?

Regards,

Off topic slightly, are you happy with the cyl. heads ? I have been looking at them and the pricing is hard to beat. I ran a 468" RAT with "990" GM heads and a Victor Jr. w/ 850 Bill Mitchell carb and felt that I might have been slighty undercarbed ?

Michael Pliska 07-30-2009 11:42 PM

Re: Intake & Carb Recommendation for 481" BBC
 
Quote:

Originally Posted by Tim H (Post 132639)
Off topic slightly, are you happy with the cyl. heads ? I have been looking at them and the pricing is hard to beat. I ran a 468" RAT with "990" GM heads and a Victor Jr. w/ 850 Bill Mitchell carb and felt that I might have been slighty undercarbed ?

Tim,
So far I am happy with them. The chambers seem to have more of a "point" between the valves than others (the inside point if you think of it as being heart-shaped), which required a little surgery on my pistons. Another friend who used the same heads just dremeled out the combustion chambers, but I figured my pistons were old and the heads were new. In retrospect I would have probably cut on the heads instead. I previously ran iron LS7 heads and a smaller cam (0.660" lift), everything else the same. The older combination ran a best of 6.08 in the 1/8 mile, typically 6.15-6.20. With the head and cam change it is running 5.98-6.00 in the same conditions the old motor ran 6.20 or so.

My only gripe with Patriot was in getting my order straight (I added some parts to the order and they didn't catch them in the first shipment), otherwise they were great to deal with. I got the equivalent of their "0.800 lift" heads, which come with 2.300 intake valves despite the website indicating 2.250. They were willing to work with me on a custom package, as I didn't want the springs (using a near-new set I had), and cutting for my bigger springs. They had great prices on the other components like ARP head bolts & chrome-moly pushrods. Keep in mind that they require longer pushrods and head bolts/studs (which their website should mention but doesn't).

Regards,

Tim H 08-02-2009 09:53 AM

Re: Intake & Carb Recommendation for 481" BBC
 
Ok, thanks for the feedback. Good to know about the pushrods and head bolts up front. Their heads also have a raised exhaust port I believe,which I think is not really prominently mentionned in some of the descriptions.

Michael Pliska 08-02-2009 12:27 PM

Re: Intake & Carb Recommendation for 481" BBC
 
Quote:

Originally Posted by Tim H (Post 132981)
Ok, thanks for the feedback. Good to know about the pushrods and head bolts up front. Their heads also have a raised exhaust port I believe,which I think is not really prominently mentionned in some of the descriptions.

Yup, they are 0.400" raised, which was a pain for me as I had just built a set of headers using both stock LS6 heads and angle-milled L88 heads to mock up for. I eyeballed it for fitting raised-port heads, but ended up having to do some surgery to get them to work. Glad I hadn't had the headers coated yet!


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