Rack and Pinion vs engine setback for header clearance?

[ne57]

I've been eyeballing, measuring, and brainstorming for this engine swap. Early(1957) 392 hemi into a 66 dart with SB 727, anicipated HP maybe 450, torque maybe 500+ftlbs?(stock 392 hp=325 torque=430 so this would be a comparitivley mild hemi) One of the major hurdles will be header clearance. Looks to me like the left block hugger shorty header will hit the steering box. Its gelling in my head that there are 3 approaches to this problem.

1) set the engine back(and maybe up) until the downtubes clear the box. This means moving the firewall back oh maybe 4 inches or so. Also means the trans mount may be problematic. Ok a new or modified lower cross member could be fabricated. But I wonder if the torsion bar crossmember that goes 'over' the trans will restrict how high or back the 727 can fit in the tunnel because now the crossmember may be over the bulkier maincase instead of the slimmer tailshaft. I don't think I'm confident enough to start chopping up the torsion bar mounts. Oil pan mods are likely but maybe not overly complicated. Possibly a front sump?

2) swapping to a rack and pinion will eliminate the steering box problem and therefor maybe no engine setback at all, or maybe just a smidge. . I see its been done a lot but my concern would be what could happen in a catastrophic failure. Looks like the K frame has to be cut or notched to make the rack fit and this is a heavy engine (apx 750 lbs.. a good 250lbs over the /6 weight) plus a whole lot more torque. Will the K frame strength be compromised enough to cause serious problems? I've read bump steer can be a problem with converting to a rack. Anybody done a big block swap AND rack and pinion?

3) Ditch the headers and just go with stock, cast iron exhaust manifolds, which I also have on hand. Will still be a shoehorn job but will fit with mount spacers etc. Its been done. Possible engine setback about 1-2 inches? This puts the engine just about stock location so transmount should not be a BIG deal. I have a center sump pan that may work directly or with minimal mods. I'm reasonably sure I have a dropped centerlink but if not one could be gotten. BUT, I have the headers and it'd be shame not to use them, That'd be like throwing horsepower away? But at what cost? All those mods mentioned above?

Boils down to either go with a safer(?) outcome by setting back at the expense of ALOT of work...or have a potential risk by cutting up the kframe but the job should be alot simpler, overall...or keep it simple stupid and go with cast iron manifolds at the cost of power.

This will be a street car mostly. Dependability, durability and safety are major factors. But its still a hotrod, if you know what I mean.

I am so glad I have all you guys to bounce ideas off of. All my hotrodding friends from the old days have moved away. So any who want to weigh in with facts, figures or even conjecture..I'm all ears.

Once I actually start work I'll start a new thread for posterity, but for now short threads on particular subjects might work better for getting the input I need?

thanks much

 

[Vic Storm]

The stock frame held the hemi motor in 68 so it should be plenty strong but there arer a couple different ways to go. AlterKation front suspension would open the whole thing up but they are close to $3000. Mancini also makes a tube K frame w/rack-n-pinion mounts. That too opens up the motor compart, the alterkation actually allows you to remove the inner fenders and shock towers.

 

[ne57]

Here's some pics of my exhaust options and how they fit or don't fit around the steering box. In some I laid the header/manifold about where it comes close to clearing the box. Some others show how the exhaust(s) fits around the block.

This was just to get a visualization of how far back the motor would have to go, if I chose that route.

As you can see, the 4tube headers would at least touch where the firewall is now, so add some for the block and its on the order of a 4-5 inch setback, not an insignificant amount to move a firewall and tunnel. Its not as bad with the iron manifolds but still needs setback of some sort. Because of the angle of the front pipe of the headers when viewed sideways, raising the motor up will aid in clearing the box. But there's a limit.

Of course I have the rear mounted distributor to deal with too, don't want to bury that. Setback can only help a front heavy weight distribution. How bad do I want to use the headers?

At some point I'll crawl under the car and see how a rack might fit.

*continues to scratch head*

 

[billyjay]

Dont let anyone tell you it cant be done..I just finished installing a 572ci Indy Maxx Motor with 727 trans in my 63 Dart..there are a few small issues but nothing major..if you use the stock K-memeber..Notch it and rebox it in for strenght.. it will be fine.. i mocked up a bare block and trans to get location on my motor.. used the factory trans mount and then bolted motor plate on front of motor and then used a pc of 1 1/2 square tube and clamped it to the back of the motor plate and welded down my tabs to bolt my motor plate to... then i removed the trans bolts and slide the motor back to the new tabs and then made sure the motor/trans was square and rebuilt the section of trans cross member..now my motor was moved back 1 1/2" it is about .050 off the firewall and can still remove the valve cover.. oil pan wa an issue for me cause i have a magnum force k-memebr and no one makes oil pans for that set-up in the early A-body.. built my own..took 2 days..if you are going to do this engine mod..i would suggest you cut and remove the firewall and trans tunnel. do your build and then rebuild the firewall with some 22ga sheet meatl took me about 2-3 days to build all of mine..

 

[ne57]

Billyjay, I took some time to look over your photos. Man, your Dart is inspiring! Truly Hot Rod Art. I'm not planning on getting that deep on my build, I'm just looking for a fun street ride, but I think I'll be spending hours studying your pics for ideas.

Its most helpful to see your chassis work pics in progress. Gives me a better idea of how the stock frame is put together, without the sheet metal to obscure the view. Like the trans crossmember...I can see that indeed my suspicion was right, not a lot of room there if the tranny has to go way back and have the main case under that hump.

I still am looking around for good insight on just how a rack and pinion conversion would work. Stuff like exactly where the rack should be located re: the rest of steering linkages, what's gonna be the practical implication of swapping the spindles side for side in a street application that has to pass DMV inspection.

If I can do the rack, my biggest issue will be solved, but I need to be sure that its safe(especially if I do the work, lol).

Anyway, Thanks for the great photos, immensely helpful.