Boost estimate, please....

If someone with experience with Mopar 360 blow-thru V-1, S-trim installations could answer this, I'd surely appreciate it.

I am installing a V-1, S Trim Vortech on a 360 Magnum (crate motor type) with an aftermarket cam (214/218 degrees at .050" lift, with .525" lift, and 114 degree lobe separation), a 780 Holley double pumper, and TTI (stepped) headers. It is otherwise bone stock.

It will be in a '72 Duster (3,300 pounds), and will have the appropriate pulleys to spin 50,000 rpm (the limit) at 6,000 engine rpm (also, the rpm limit.)

I would like to know *approximately* how much boost this setup will produce.

I realize it's impossible to tell EXACTLY, but the techs at Vortech would not even venture a guess.

I only am looking for an estimate.

Can anybody help?

Any information will be appreciated.

Thanks much!

Bill, in Conway, Arkansas

14#s or so.

I do appreciate the information, "19".


I hope you're right about that. I was hoping for about 5-6 pounds, and 90-100 hp increase, but these small-port heads will probably create so much restriction, that 12+ pounds is likely. Still, if I can get an additional 100 hp, I'll be a very happy camper!

Thanks again.

Bill, in Conway, AR.

50K RPM is spinning the S-Trim, certainly not the max it can do, but it should make some boost. I am by no means acquainted with the particulars of Mopar parts and just basicly estimated based on a good H/C/I stroker 302.

Thanks for the note.

I had read that 50,000 rpm was the safe design limit for the S Trim V-1. Beyond that, I read that you run the risk of the impeller deflecting and getting into the scroll housing and damaging it.

Is this not true? Is there a safe limit, and if so, what is it, please.
I have the pulleys sized to give 50K at 6K engine rpm, now. I don't really want to run the engine beyond that, nor do I want to take a chance on damaging the blower.

Help.... :)

Well the main consideration is by spinning this blower way beyond its efficiency range am I really doing myself any good and am I compromising the safety of my tune. If you are running a boost cooler then yes you will benefit, if not with a Vortech you will probably still benefit as they are rather efficient.

I have spun the crap out of A, S and T-Trims without a problem, they are a rugged design and Vortech must have taken a page from Boeing when they published the design tolerances. The possibility of the things you described happening is plausible but rare.

I have a Snowperformance Boost Cooler that I will install as soon as the blower installation is finished. I still have to install a fuel system that will include a Holley Black pump, a boost-oriented fuel pressure regulator, filter, and 3/8" line and an in-tank pickup unit, to replace the 5/16th OEM line that is on there. The plan is to start spraying the alky/water mixture at 3 psi of boost...

I also have an adjustable MSD boost-oriented spark retard module to keep detonation at bay... hopefully.

A "Carb Shop" blow-thru 750 Holley double pumper will handle the fuel mixing chores, and was dyno-tested to 15 pounds of boost for mixture accuracy, according to them.

I have a stock reciprocating assembly, with hypereutectic pistons, and stock, composition head gaskets, so cannot afford even a HINT of detonation, or kiss it all goodbye...

I plan on limiting it to 24 degrees of spark advance under boost. Think that will work? I've always run 34 degrees under no boost...

Any advice and info will be appreciated!

With the Meth that timing should be okay. Again I don't know Mopar very well but on a SBF that would be more than safe. As far as the rest of your combo I think it should work well. Should make some excellent power. On a 5.0L setup it would be in excess of 550 rwhp I believe.

Thanks a lot for the generous estimate!!! That's a lot more hp than I had counted on; I sure hope you're right.

These Magnum (cast iron) OEM heads have a 3-angle valve job, some minimal bowl porting and back-cut valves, but otherwise are really pretty much stock, and don't flow very well on the intake side.

Still those extra 58 cubic inches (it's a 360) should contribute SOMETHING.

Car weighs 3,500 pounds with driver, and went 13.35 (1.91, best 60-foot) on 8" drag radials, unblown, with stock cast iron (340) exhaust manifolds.

I am hoping to be able to run 12-flat with this Vortech, after adding an Air-Gap intake manifold. The other manifold was a water-heated (lo-rise), and the car now has some nice, stepped (1-5/8"-1-3/4") headers, with a 2.5" mandrel-bent exhaust system.

Do you think this is a reasonable assumption, that it might be able to run 12-flat at about 112? It ran 102 with the N-A setup...

Thanks again for your time and attention; I REALLY apprecciate it. There are some GN Buicks I am wanting to play with... :) They run low 12's and some can manage mid-11's, but I am working on that....

Bill, in Conway, AR

I can only give my own car as an example. I have factory style heads that flow sub 200 cfm in the .500 area. The cam I have is close to yours and you have me beat handily in the cubic inch arena. I would imagine that carb intake is going to flow better than my EFI intake and the adiabatic cooling of the carburator along with the meth is going to help. I made 502 rwhp with my setup no meth and 11-12#s out of a T-Trim which should be about equal to your S-Trim setup with the pulley combo you have. Taking into account the extra boost and the methanol I think you will at the very least go over 500 rwhp drivetrain dependant.

If you are running a loose convertor then you may not get the glory numbers but it will still scoot faster than the manual. My car at about the same weight with a 5-speed ran a 12.1@121 mph with a 2.5 60' with my old S-Trim setup which made 488 rwhp. So yeah I think you will achieve your ET and mph goals pretty easily.

The converter I have is a 318 unit that is designated "hi-stall", but isn't, really. I have a 2.73:1 center section that I run for the highway, sometimes, and with it in, (and the reduced torque multiplication), I can hold the car dead still with the throttle floored (I am talking normally-aspirated, here.) Throttle on the floor, it stalls at 2,500 rpm. I wouldn't call that a very "loose" converter, but this mild cam has so much low-end torque, I don't think I need any more stall speed than that, do you?

BTW, my compression ratio is a true 9:1. I cc'd everything...

Getting the car to hook has been a problem, but I may end up putting some 10"-wide slicks on it if the wheelspin persists. I think that with the proper gears and tires, I should be able to pare my 60-foot times down to maybe high 1.70's, with the blower.

Talk is cheap; we'll see...

Thanks again for all your help. It has been a Godsend!!!

Good luck with your 'Stang; sounds like a neat (and, fast) car!!!

Thanks man same to you.