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is a tunnel ram right for me?

6K views 55 replies 19 participants last post by  thatguy 
#1 · (Edited)
So i'm contemplating buying a Wieand tunnel ram with dual 600 VS holleys.

Its a 496, bigger valve, mild worked oval head, .630" lift roller cam, that currently has an 850 DP on it.

I've just spent a few hours reading about tunnel rams and carb tuning using the search tool.

I guess I've just always wanted one, but is it worth it? Its just a lake boat that i don't need every inch of power out of, but it seems like they really are a great intake. It seems properly tuned they don't produce any noticeable increases in fuel consumption, but wake the throttle response all over the RPM range.

Next question is, is the 600 VS not enough on a 496, I'm not going to use the 660's but most guys are saying the 750s are better than the 600's. Could the 600's just be jetted bigger? Or is the VS just gonna cancel out the benefit of wicked throttle response while waiting for the vacuum signal?

Sorry its so wordy, I just keep going back and forth...and back and forth again.
 
#2 ·
I've got two 600 DP's on a 565 that pulls very hard to 7500. If you think about it, 2 600 VS's just running on the primairys is still 600 cfm which is almost 2/3's the flow of the 850 wide open. There are also kits available to convert to mech. sec., from Quick Fuel among others. If you stay with the vacumn, Quick Fuel also makes quick change kits that allow for tuning.
 
#3 ·
So i'm contemplating buying an Offy tunnel ram with dual 600 VS holleys.

Its a 496, bigger valve, mild worked oval head, .630" lift roller cam, that currently has an 850 DP on it.

I've just spent a few hours reading about tunnel rams and carb tuning using the search tool.

I guess I've just always wanted one, but is it worth it? Its just a lake boat that i don't need every inch of power out of, but it seems like they really are a great intake. It seems properly tuned they don't produce any noticeable increases in fuel consumption, but wake the throttle response all over the RPM range.

Next question is, is the 600 VS not enough on a 496, I'm not going to use the 660's but most guys are saying the 750s are better than the 600's. Could the 600's just be jetted bigger? Or is the VS just gonna cancel out the benefit of wicked throttle response while waiting for the vacuum signal?

Sorry its so wordy, I just keep going back and forth...and back and forth again.
well...since you have all winter to think about what to do...i would give some consideration to a better set of heads (rect port)...a good sgl plane manif (Brodix, Dart, Team G)...perhaps an upgrade on the ign ststem...re-work the 850 carb to flow better or maybe a 1050 Dominator...these are just my suggestions & perhaps $$$ spent in a better way :)...T/R's are nice & pretty, but, except for showing off, MHO is, you can make a 1x4 set-up work just as good with less headaches :)...its just a lake boat, not a racer!...just sayin' my .02 cents :)

FastRat
 
#4 ·
changing an intake ain't no big deal. try it, you don't like it, change it back! 2-1850
holley's are a very forgiving setup! won't take much to get them tuned right, and you
will find that throttle response won't have suffered, and will pick up midrange and top
end! and will look cool too! :p it's an oval port ram, right?:)sphss
 
#7 ·
Yea just give it a try, T/R with carbs are pretty plentiful out there right now. They are much more than just "showing off" as some may have you believe. And for a lake boat that has a driver that is not afraid to keep the pedal mashed down for more than 100ft at a time then you will see what i mean when all that carburation comes alive. You have to want to use them to their full potential.
 
#8 ·
On a 496 i would be looking at a set of aftermarket heads before a TR setup. Sure you'll probably gain a few Hp with the TR but a good set of heads even with a single carb will net you far more Hp gains. By the time you buy a TR, carbs, linkage and a new scoop or tray you could probably find a good set of used heads, check 'em over and throw on a set of new springs and gain 100-150hp.:)
 
#9 ·
Keep 'em coming, I like hearing where people are coming from.

But what about jetting and power valves and metering of the 600's? And what about the VS? Should I convert to mechanical secondaries, or will the VS be okay? If I find its running lean would jetting help, or would bigger carbs be in order?
 
#13 ·
Bigger carbs won't make it run richer. The first thing I'd do to the 1850's is increase the PV metering passages by about .010". You have secondary jet plates, not metering blocks so secondary jetting is tricky. I'd have the secodaries coming in at about 2500rpm which can be adjusted with the diaphragm spirngs. Squirters and pri. jets and PV's should remain stock to start, and go from there. Make sure your timing is set or you can chase your tail with carb tuning.
 
#11 ·
PA, I would look to a different brand of T/Ram than an Offy! Weiand, Edelbrock seem to make better performance than the Offy! The heads you have maybe holding you back also! For Carbs I like to go with the classic DP in a 650 to 850 CFM to get the most bang for your buck with a T/R! JMO! WT:)devil
 
#21 ·
What kind of boat, is it a v-drive or jet ?

What type of boating do you do the most ?

What's your target rpm range? Cam and max rpm your shooting for?
Edit.


S CP
 
#30 ·
and don't forget to add an equalizer line to tie the diaphrams together!

(GN7, Can I get a pit chair w/ my name on it? or is the waiting list still too long?);)
 
#45 ·
PUT A LOADER on it and check it again! bet it comes down to the 5500-5800rpm range!
remember Agressor impellers are about 1 step steeper than your standard berkley;)
 
#53 ·
If you just have the stock rock grate on it right now, GET A LOADER from tom,
can almost guarantee you will be happy with the performance it will give over a stock
grate- tell him you want an open center-hell, he will tell you what you need;)
 
#54 ·
When I built the Miller 454 BBC, I never even questioned what was going on top.
Polished TR with 2 holleys. Not a racer, "just a lake boat".

I knew I was going to put Brodix heads on it though, the smallest rect. port head they make.

So I found a used polished wieand with 2 660's all set up, fuel plate all polished ready to go with lines and all.
Runs awesome. .565 hyd. roller.

My wife calls our boats "Show Off" boats, and She is right.
Why do we build these lake boats with big, loud, shiny engines with no intention of racing?????
To go fast AND show them off.:)devil:)devil

To that end, a TR is the only choice shy of a blower.

Put it on!
if you step up the heads later to rect. port, just sell that one and get another used one that matches. They are for sale all day long at $250.00 or so.

Get 6' of #6 summit braided hose, a handful of hose ends. a hose cutter and plumb it up!

Sure, our engine may make some more HP on a dyno with a finely tuned single set up, but I don't care, I don't race in any events.
Thing does 86 MPH, turns a stainless A to 5800 RPM (625 HP) Has instant throttle response and pulls hard all the way up, AND looks cool!!
 
#55 ·
When I built the Miller 454 BBC, I never even questioned what was going on top.
Polished TR with 2 holleys. Not a racer, "just a lake boat".

My wife calls our boats "Show Off" boats, and She is right.
Why do we build these lake boats with big, loud, shiny engines with no intention of racing?????
To go fast AND show them off.:)devil:)devil

To that end, a TR is the only choice shy of a blower.
Nice looking boat but to really show off you need to polish those heads!!! lol :p:p:)hand
 
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