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SBC Tunnel Ram

General engine tech -- Drag Racing to Circle Track

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marvingvx
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SBC Tunnel Ram

Post by marvingvx » Fri May 22, 2020 12:32 am

Discussion on Small block tunnel rams. Its going on a Big cube BowTie block 4" stroke Heads flow just under 340 cfm street driven to the 1/8 dragstrip, (sleeper with exception of what pokes through the hood LOL). 12.5-1 probably E85, peak around 7200 and shift at 7700+- in a 3900lb short bed 1500 pickup. Whats the group think? Pitfalls, manifold design and architecture pro's and cons, and other input. Done a lot of Strip Dominators and Super Vics but my first exploration in to tunnel-rams grateful for all help and advise.

marvingvx
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Re: SBC Tunnel Ram

Post by marvingvx » Fri May 22, 2020 2:41 am

Mistype ↑↑above↑↑ 7700 shift at 8200. Big Joe is the victor ram the way to go?

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Re: SBC Tunnel Ram

Post by Coloradoracer » Fri May 22, 2020 6:17 am

Runner length and size will determine how it performs, along with plenum volume. Generally a tunnel ram will outperform a good single plane, and usually moves the power range up in rpm....BUT......longer, smaller runners and smaller plenums tend to favor lower rpm performance, where larger plenum volumes and shorter, larger runners tend to favor higher rpm... Whether or not it will perform well on your combo will require testing. Just like anything, it needs to be matched to your combo to gain the most benefit. Just bolting one on may not net the gains you might expect.....
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Re: SBC Tunnel Ram

Post by ClassAct » Fri May 22, 2020 9:53 am

If you select the cam timing based on the TR and spend the money on carbs with someone who knows what they are doing (@MarkWhitener) the TR will out perform everything.

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Re: SBC Tunnel Ram

Post by Walter R. Malik » Fri May 22, 2020 10:05 am

marvingvx wrote:
Fri May 22, 2020 12:32 am
Discussion on Small block tunnel rams. Its going on a Big cube BowTie block 4" stroke Heads flow just under 340 cfm street driven to the 1/8 dragstrip, (sleeper with exception of what pokes through the hood LOL). 12.5-1 probably E85, peak around 7200 and shift at 7700+- in a 3900lb short bed 1500 pickup. Whats the group think? Pitfalls, manifold design and architecture pro's and cons, and other input. Done a lot of Strip Dominators and Super Vics but my first exploration in to tunnel-rams grateful for all help and advise.

Personally, I like the later Weiand, (whish is no longer sold new), mainly because the runner length can be adjusted easily with spacers.

Used is the only way to get one now days ... every once in a while one is in "Racing Junk" or "Ebay".
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Re: SBC Tunnel Ram

Post by marvingvx » Fri May 22, 2020 10:43 am

ClassAct wrote:
Fri May 22, 2020 9:53 am
If you select the cam timing based on the TR and spend the money on carbs with someone who knows what they are doing (@MarkWhitener) the TR will out perform everything.
Leaning toward 660's with metering blocks w/4 corner bleeds. Cam solid roller 264\268 @.050 109+4, considering a little more aggressive and more exhaust in case I decide to spray. If I make it a tad longer I think I could run it on pump gas instead of E85?

To keep it driveable on the street I may be stretching it a bit for a 3000 stall? Should I dial it back to 10" or so vacuum?

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Re: SBC Tunnel Ram

Post by F-BIRD'88 » Fri May 22, 2020 11:01 am

You are not going go go very far on pump gas with 12.5:1 cr.

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Re: SBC Tunnel Ram

Post by rfoll » Fri May 22, 2020 11:04 am

marvingvx wrote:
Fri May 22, 2020 2:41 am
Mistype ↑↑above↑↑ 7700 shift at 8200. Big Joe is the victor ram the way to go?
In case you didn't know, Joe Sherman passed away about a year ago.
So much to do, so little time...

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Re: SBC Tunnel Ram

Post by Steve.k » Fri May 22, 2020 12:38 pm

Joe was a big advocate of tunnel with dual carbs. He was the main reason I switched my sbf to duals.

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Re: SBC Tunnel Ram

Post by novafornow » Fri May 22, 2020 12:38 pm

Bad choice of carbs.

marvingvx
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Re: SBC Tunnel Ram

Post by marvingvx » Fri May 22, 2020 12:51 pm

rfoll wrote:
Fri May 22, 2020 11:04 am
marvingvx wrote:
Fri May 22, 2020 2:41 am
Mistype ↑↑above↑↑ 7700 shift at 8200. Big Joe is the victor ram the way to go?
In case you didn't know, Joe Sherman passed away about a year ago.
Greetings to you and Walter it's been awhile since I've been on here. Now that you mention it I remember being told that that PRI his year. Sad to think about, please accept my apologies if it stirred up up any memories.

Also hoping Randy 331 doesn't come in here with his banter once again LOL

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Re: SBC Tunnel Ram

Post by BrazilianZ28Camaro » Fri May 22, 2020 1:16 pm

You didn't mention, but if your engine is a 434 SBC, a Victor Ram and Holleys 750s will be perfect for your combo BUT E85 might be problematic with a non heated intake.

You'd be better with less CR and gas instead. Its a very good idea have full adjustable carbs with removable air bleeds, idle feed restrictors and all.

T-ram will ask you for two times more precision on the adjustments and will outperform a dual plane on low revs and a single plane at high revs on most applications.It have the runner lenght and plenun size to do just that.

Get a real converter like 4500 rpm ,built for your combo/aplication. Your truck will be a blast on the strip.

good luck
'71 Z28 street strip car
Pump gas All motor SBC 427
3308 lbs-29x10.5 Hoosiers
NEW BEST ET
1.40 60' / 4.05 330' / 6.32@111.25mph

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Re: SBC Tunnel Ram

Post by 555RAT » Fri May 22, 2020 2:58 pm

I spent last season dialing in a tunnel ram on my sbc and from that experience I would say your shift rpm is probably a bit high for that cam and size engine. I run a 3.8 stroke, 14:1, 414 with a 276/284@.050” with 2 qft 950’s and not seeing much ET difference shifting at 7500 or 8000 so I shift at 7600. Smaller carbs will be better on the street but if you’re converting carbs to 4 corner idle be sure and plug the channel connecting the primary and secondary in the baseplate. Whatever you do stick with it, you’ll love the tunnel ram!
Keith

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Re: SBC Tunnel Ram

Post by Old School » Fri May 22, 2020 3:41 pm

ClassAct wrote:
Fri May 22, 2020 9:53 am
If you select the cam timing based on the TR and spend the money on carbs with someone who knows what they are doing (@MarkWhitener) the TR will out perform everything.
What would you do different for cam timing on a TR compared to a good single plane and dominator?

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Re: SBC Tunnel Ram

Post by ClassAct » Fri May 22, 2020 4:47 pm

Old School wrote:
Fri May 22, 2020 3:41 pm
ClassAct wrote:
Fri May 22, 2020 9:53 am
If you select the cam timing based on the TR and spend the money on carbs with someone who knows what they are doing (@MarkWhitener) the TR will out perform everything.
What would you do different for cam timing on a TR compared to a good single plane and dominator?

Less at .050 and tighter LSA.

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