'72 Valiant Prepare for Power!?

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Hyper72Valiant

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Just got back from my machine shop today after a dyno pull on my 408" Stroker...570HP and 475ft/lbs. of Torque! They said I might have to de-tune to make it work in my car. I don't want to de-tune at all, who would?! This is going in a '72 Valiant 4 Door that had a slant six (engine is toast), so, lot's of things need to be done of course. I just never thought my engine configuration would make so much power!
"I have never even seen a Chevy hit that" is what the dyno operator said, haha! He should have got a Mopar!
I have a 3.55 Sure Grip in an 8 3/4 going in, brand new 727 with torque converter stall ~2500, Poly-Loc Schumacher Mounts. I will need a driveshaft of course, should I look for anything special? Planned on 245/60/15 in the back, 205/65/15 in the front (that would make the car look parallel to the ground right?) but will that be adequate?
My main question is, what am I going to need so that my car can handle the power and I will be safe? I thought subframe connectors, but will that be enough? I don't want my car to turn into a pretzel when I lay on it. I like having a full interior, so, if I can steer away from a roll cage than I will. Please guys, I need advice from the pros and that's you.
Thanks,
Cory
 
connectors, torque boxes.

I'd put a roll bar in it. You can bend the rear bars to run up high along the roof, then cut down to the trunk area through the package tray speaker holes. Here's a friends Valiant with a Morrison bar, IIRC, bent for "save rear seat" option. Cast about $40 more than a standard roll bar.

4766143-33.jpg





You need a rigid chassis, that engine will twist that car up really good.
 
The Morrison bar looks good, I don't see any other places that sell their roll bars with a "save the rear seat" option (I do want to be able to use the rear seat, this is a 4 door). I do want to use the rear speakers...maybe I can take the tubing just to the outside of the rear speakers? Jegs, Summit, Chris Alston Chassis, S-W Race Cars, that's all that I have found so far that sell Roll Bars.
This will be a street car, but I would like to take it down to the local track and see what E.T's I can get. As for Torque Boxes, from what I understand they reinforce the mounts for the leaf spring hangers? I found torque boxes at The Paddock. As for Frame Connectors, what is preferred: bolt in or welded? I would think welded would be far better.
What about a pinion snubber,is that necessary? What is the goal of the pinion snubber? Thanks for the picture of the roll bar by the way, it's always good to see a visual.
 
Weld-in frame connectors would be better. The pinion snubber is supposed to keep the rear axle from winding up. It needs to be about an inch under the floor pan. What are the details on that 408 build?
 
Excellent, a 4 door sleeper, them's the best kind. Yes to welding up the connectors and installing an imaginative roll cage to get some rigidity into the car. I'd also mini tub her to allow for some fatter boots, around 295-60x15 or she's not going to want to plant.

terry
 
nice power. and you'll definitely need bigger meats to hook..weld in sub-frame connectors are a must on even a slant 6 car. a cage would be a good help...
 
Here is a video I took of the Dyno run!

http://www.youtube.com/watch?v=51Wl2evuTSc

I don't have all the specs yet, they are having an open house this Saturday and are showcasing my engine! Woohoo! After this Saturday they will crate it up and I will get all the specs on the engine.

Just out of curiosity, that gauge shows the Torque...well, once he found out the torque he said he figured in other variables such as barometric pressure, temperature, etc...and then calculated the Horsepower. Is it weird though that my horsepower is a way higher number than my torque? I thought that the horsepower and torque numbers were usually pretty close together?
 
Cut new holes for the speakers.

I doubt there is enough room to run the bars on the window side of the shelf. It's also too tight for the tube bender to get right unless you custom bend those bars. You have to call and ask about that saver option.

Good luck with it
 
I have been playing with the same problem with my '67 valiant on keeping the back bench. if you go outside of the speak holes you are ending your bars on top of the rear wheel-wells, not were you want to be. If you go in between the speaker holes the rear down bars will tie into the main hoop too close to each other IMHO. GO through your speaker holes and make new home for said speakers like Crackedback sugested would be best.
I talked with S&W awhile back and they were willing to sell me there roller bar kit and leave the rear down bars extra long for same price so that I could take them down to my local shop to have bent were I felt best matched my aplication, if you can't get a kit already pre-bent. I've heard some of the tracks are a little fussy about this bent bar stuff, so you may want to check your local track for what they interpet (sp) how much of a bend and how far etc. before you install the bars.
 
All great answers guys! What do you guys think...should I get these things installed before or after I get the new engine put in? I have a guy ready and willing any time I am, he isn't busy for the next 30 days so I have a little bit of a crunch. Heck, he might be able to install the roll bar, subframe connectors and torque boxes too, I need to make some calls.

What would you guys say the max HP and TQ with the roll bar, torque boxes and sub-frame connectors installed on a car are (just as a future reference)?
 
As I suspected, after talking to the shop, they actually calculated my HP at sea level, so at sea level my HP would be about 570, but here in Utah I am at 450HP and Torque is still the same at 475. I am still very pleased!
The machine shop said I might not really need a roll bar unless I get some slicks on there, but said Torque Boxes and Weld in Subframe Connectors are still needed. I don't really plan on putting any slicks on the Valiant, this is mainly a street car and probably won't get any slicks for the drag strip for many years.
 
Hyper72Valiant said:
As I suspected, after talking to the shop, they actually calculated my HP at sea level, so at sea level my HP would be about 570, but here in Utah I am at 450HP and Torque is still the same at 475. I am still very pleased!
The machine shop said I might not really need a roll bar unless I get some slicks on there, but said Torque Boxes and Weld in Subframe Connectors are still needed. I don't really plan on putting any slicks on the Valiant, this is mainly a street car and probably won't get any slicks for the drag strip for many years.
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That seems more like it. For your engine to have peak HP/tq numbers like that would indicate either a smaller, higher-revving engine or one with perhaps way too big of a cam... I would also say torque boxes and subframe connectors are enough to handle that. It's when you get into more serious strip action that you'll need a rollbar/cage.
 
That Roll Bar looks nice! I agree, I was really confused when they told me 570 HP! I was blown away and I asked if that was really true, which it was but at sea level. They left that little tid bit out. Does anyone have pics of Torque Boxes installed?
 
Just put in welded frame connectors and s/s springs. I run my Scamp like that except it is mini tubbed and springs relocated. it pushed 500.9HP@535ft lbs and it does fine at the track.
 
What weld in subframe connectors are the strongest? I have found a lot of places that carry there own version. I want to do this right...Big Block Dart. com's Archives are amazing! Got a full write up of how to install frame connectors as well as a lot of other things! Gives you a better understanding of what's really going on :-D
 
if i was you id at the very least relocate the springs...a full mini tub is alot of work (but definatly worth it) but if you'd rather not tackle it even the offset spring kit should allow you to run between a 255-275 tire under there if im not mistaken...with all the power, traction will be an issue lol...frame connectors are definatly a must, and while your at it i'd stick a driveshaft safety hoop in there...not many recommend them for a street car, but they are cheap and you wont be having your car catapult like a polevaulter if the shaft ever comes out or apart...just my opinion

as far as frame connectors go, i think its wiser if you make a set of your own...shouldnt cost you more than 50 bucks, and if you can borrow a welder or have a friend who welds you can have them in in a day

good luck with it! sounds like its gonna be a blast!
 
Run the connectors through the floor and into the rear rails and plug weld them. Tie them to the front of your relocation boxes if you go that route.

Burntorange, Russell, had some pics of running them through the floor.
 
mshred said:
as far as frame connectors go, i think its wiser if you make a set of your own...shouldnt cost you more than 50 bucks, and if you can borrow a welder or have a friend who welds you can have them in in a day
Click to expand...

I'll second that. I have under $20 in mine and they're just as good as any aftermarket ones. I just bought about 10 feet of square tubing and welded them in myself.
 
I just imagined my car pole vaulting :( Will be getting that driveshaft hoop now...ya, I can't see frame connectors being too difficult, I know of a place where I can get the metal too. So, cut a little in the floor pans so that the connectors can stick out a bit where peoples feet are? Sorry, that sounds stupid but it's 3:30 am, I have a good excuse :)

I found this picture posted by Burntorange on another thread, this is what you meant right?:

 
Hyper72Valiant said:
I just imagined my car pole vaulting :( Will be getting that driveshaft hoop now...ya, I can't see frame connectors being too difficult, I know of a place where I can get the metal too. So, cut a little in the floor pans so that the connectors can stick out a bit where peoples feet are? Sorry, that sounds stupid but it's 3:30 am, I have a good excuse :)
Click to expand...

yea man honestly its just cheap insurance to put a hoop in...i built mine out of some flatstock my dad found at work, but summit sells universal kits for like 30 bucks...you cant go wrong for that price...dont forget to check the nhra rulebook for the minimum thickness it has to be that way you wont get hassled by tech if the need arises
 
I think they tried to make a car pole vault on Mythbusters & couldn't get it to happen. Driveshaft hoop is still a good idea though. Who knows, there's a first time for everything.
 
Ya, they did do that on mythbusters, but it wouldn't launch. It did do serious damage to the car however
 
Awesome numbers on that engine. That is going to be lots and lots of fun!!!
Did they give you the specs on the engine? What heads intake cam ect?
 
Aaron said:
Awesome numbers on that engine. That is going to be lots and lots of fun!!!
Did they give you the specs on the engine? What heads intake cam ect?
Click to expand...


Thanks! I will post the specs as soon as I get the blueprint, I made this engine so that if I wanted to add nos or do anything else for power later on it would be able to handle it.

By the way, if anyone wants to see some pics of the '72 Valiant, I have some on cardomain:

http://www.cardomain.com/ride/2204703
 
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