dual plane to single plane?

[custom442]

I've driven my car around enough now I can get a good idea of where it starts making good power. It pulls nice down low but really sets me back in the seat above 4500 rpm.

My guess is I'm around 450 hp/tq with my setup. If I open the headers and have a ported single plane, it's not out of the question that I could hit above the 500 hp/tq mark, the carb, cam, and heads are really looking to breath on the top end. If I cant feel my butt hit the seat until 4500 theres no reason for the dual plane, should I add another 30-50 hp on the top end? This is why I'm thinking about swapping for a vic jr. single plane.


heres the specs:
282 extreme energy comcams, 230/236 dur @.5 lift,
dual plane rpm air gap
holley 770 street avenger
patriot perf. freedom series heads - 195cc intake runners, pocket ported, larger valves... flows [email protected], [email protected]
383 sbc, 3000 stall th350, now 2.14 gears (i think) - will swap to 2.90 or 3.00

 

[megaladon6]

if it's a regular driver, going to a single plain may kill the bottom end, for a negligible increase in top end.
what stall converter do you have?

 

[shotgun]

You know what I am goining to say, too much stall and not enough gear even after the swap.

That's why your butt dyno does not feel the hit until 4500. :lol:

Same advice, add gear first, ignore at your own peril. 😀

 

[shotgun]

Seems that Comp agrees.

Description

Part Number: Grind Number:XE282HR
Lifter Type: Hydraulic Roller Lifter Engine Family: Chevrolet 262-400 c.i. 8 cyl. 1955-1998
Description: Hydraulic Roller-Great for Street Machines, needs intake, headers, 2000 stall, and gears.
Cam Family: XTREME Energy™ Retro-Fit Hydraulic Roller Camshafts
.

 

[megaladon6]

sorry, missed the stall in the OP. though i think 3k stall is more than enough, might even be a bit too much, depending on usage.
but i see you have very low gears. definitely fix that first. they'll make a huge diff in feel and times.

 

[custom442]

Thanks guys, I do need some real gears before I can make a judgment. I'll get around 3.00 gears, dont want over than about 3.20 so that way I can take it on the highway without eating my lunch. Also want the higher gears so it'll be more fun on the street. It wont be driven that much, so the 3000 stall isnt hurting anything. I want to get real low gears, trust me, its just the fact that I dont want to be stuck with this car as strictly an around town cruiser. Of course I say this, but then you never know I could end up with a 4.86 locker a year from now.

 

[Phoenyx]

The power range of that cam is 2200-5800 RPM. So with that 3000 stall you are losing about 1000 (or more) RPM out of a 3600 RPM range. So mainly, you need to go to a 2000-2200RPM converter. And second, those gears are a big problem. What size rear tire are you running? Because the taller the tire, the worse it is for your gear situation. I have 3.73s with about a 24" tire, I like it, but not so fun turning 3500+ RPMs cruising down the highway. But then again, it's not to bad either.

Another thing, what is your engine revving at when you're cruising at the speed limit? If it's lower than your 3000 RPM stall speed, you're also cooking the hell out of your transmission.

I suggest like the others. Milder stall, and better gears. Trust me, I have built cars set up similar to yours (minus the stall). When your engine is making it's power that high in the RPM range, you don't want highway gears.

 

[patmckinneyracing]

Nothing wrong with running a mild stall with good gears. I'm running a 1900-2000 stall with 3.73 gears and runs excellent on the street. Stick with the dual plane intake, the only reason you would want to switch to a single plane is if your going for every tenth of a second in the quarter. If your driver this car on the street, dual plane is the way to go.

 

[custom442]

Okay, looks like I'll stick with the dual plane. Here's my tangent. Comments and advice are very appreciated

As far as toasting the transmission with the higher stall, I really dont care about it. It's a temporary, it's very well built (guy before me ran low 10's in it), and it was cheap. Whenever I can save the money or whenever the car is finished, I'll be swapping out a quality 2004r with a lockup converter (same 3000 stall); this will be in a few years. The th350 will last that long at mild street driving with occasional stoplight runs, I have no doubts about that. If this car were to be run hard for a few hours at the strip, and drive it back home and do this routine over and over, then yes I'd be worried about burning up the th350. Reality is, in the next few years, I'd take this car to the track at most a half dozen times. Mostly just to get an idea of how it stacks up with real numbers.

About the higher stall - this thing is not going to stall at 3000 (car is too light), I'm expecting it will be 2600-2800 when I get real gears on there. Also the cam specs show it starts making power at 2200 (which is only one little piece of the equation). I would not want it to stall at 2000 rpms, it's just personal preference.

I have a dilemma about my goals for the car. I want the quickness/performance of a 3.80-4.2 rear, but then I'm building the car as a street/handling one. Tires will be 255/50/16 all around. Rebound will be terrible and the rear is going to be loose. This is why I'm having problems deciding to set up this gearing. If I went with real low gears, I'd want to use a locker or spool, but if I went with around a 3.00-3.20 I'd want an LSD. I know gearing would only knock off a few tenths on any times I'm looking at, but I have a feeling this will be a high 11/low 12 sec car, so a few tenths would go along way when compared to the other street cars around.

So some advice here would be helpful - how do I make around a 4.0-4.2 rear hook up well with some power and also keep my tight front suspension and loose rear end? I thought about a manual locker rear like an ARB air locker, but then I still wouldn't have an LSD for cornering when it's disengaged. So I'm likely getting an LSD and just not have as much neckbreaking type fun. I heard a certain amount of wheelspin is optimum. Also thought about air bags in the rear coils and only engaging them when needed off the line (-- which would be one of the reasons of going to the strip to test out these settings), but then I'd still have the front shocks too hard.

Does someone make a type of adjustable shock system accessible from the interior of the car while driving/parked, similar to GM's ride control/auto adjusting dampers? ...somebody needs to make a 90/10 and 50/50 front shock in one :evil:

Also - is there such a thing as retrofitting an ABS system complete w/ computer/sensors, modern traction control device?