weight bias and motors

[tirod]

Showing my age. I read recently in some thread somewhere, a builder adjusted the weight bias by a very simple procedure, so to speak: he moved the motor forward two inches. But I can't find it to reference it.

I considered doing the same in the day to a '66 Mustang, it was a well known technique. albeit complicated for then. What was intended, of course, was to set it back in the unibody that far, and lots of guys looking at the next step up in performance did, regardless of make. Trunk mounted batteries and such were usually done first, I did.

In the case of the roadster and coupe, some are moving the battery to the front of the car as part of that adjustment. Exactly the same logic, it's just going the other way.

Moving the motor on an existing car is a lot like remodeling a house and putting in another bedroom - under the same roof. Existing things are in the way. It's major surgery, and no less in a production sedan. Ask the guys shoveling V8's into 32 Fords. There's a reason old rodders salvage wheelbarrow pans - they make workable firewalls.

In this case, moving the engine forward offers a lot, especially if it's done from the beginning. Unlike that proverbial remodel, if you add the bedroom before the interior walls are up, it's much more a no brainer.

Coupe or roadster, what do you get? Weight bias adjustment, for one. Next, more room for headers, especially shorties, or undercar. It won't help the traditional ones much, tho. The starter is more accessible, not jammed against the footwell. More room for insulation, too.

With cable or hydraulic operation of throttle or clutch, unlike mechanical, there's very little problem. The front of the engine has more than sufficient room, and most use serpentine anyway. The hoses don't care. Other than welding the frame, having the motor mounts two inches further forward isn't very problematic.

Out back, the driveshaft needs to be longer, and the shifter would be located two inches forward - which is some relief to the existing problem anyway. The rear trans mount could be an issue - unless you plan something in the way of undercar exhaust and need it moved. The big tube running across just locates the main tubes, and can be done differently, like a inverted K member. Again, new car work is easier, and surgery has been done by others.

I don't see a major issue with steering, hood clearance is always something. Shelby didn't have modern hi rise manifolds with carbs. We bring that on ourselves.

It's not a simple mod, but it does have advantages for those who can use them. Anything else I'm missing?

[mmarshall]

That was my thread. I was installing a LS1 and needed to change a bunch of stuff anyway so why not move the engine at the same time. The 2" move changed the bias forward by 3%, but that was with a aluminum blocked engine. That has helped the handling more than any other change I have made so far.

I think the biggest issue with moving the 302 would be the exhaust and maybe hood clearance. The LS1 is very flat and has 4" of hood clearance in my install.

[Shawnski]

Actually, you could move a SBF forward with ease. You only can gain room for exhaust by going forward (as it pulls away from the footbox areas).

In addition the scoop as molded in the hood actually provides a lot of room forward of the cowl (since it was designed to accomidate four twin-choke weber carbs). With a motor moved forward it could allow for a larger diameter air cleaner as the intake is not so crowded out by the cowl.

[Thanatopsis]

Tirod,

Paul (Stengun) moved his forward on his spyder. Here's the thread:
Moving engine forward?

[stengun]

Howdy,

Originally Posted by Thanatopsis

Tirod,

Paul (Stengun) moved his forward on his spyder. Here's the thread:
Moving engine forward?

You beat me to it!

Yep, that's what I did. I swapped the engine mounts from side to side and had to grind off a locator pin and that's it.

It moved everything forward about 1 1/2" which gives a lot more room around the bellhousing area and the starter.

Since my Spyder has a highly modified frame and custom footboxes I decided to move the engine for more room for the exhaust and weight distribution.

I'm going to use the FFR headers and custom sidepipes ( still in the planning stage ) so that not a problem.

I also didn't have a driveshaft ( I do now ) so that was one less thing to worry about too.

I had to make an adaptor for the trans mount which consisted of a 3/16" thick cold rolled plate and a couple of bolt holes and two 1/2" bolts, nuts and washers.

I'm running an aluminum headed 351W stroker so this should greatly help my weight balance.

Paul

[Thanatopsis]

Paul,

Did that move interfere with the shifter on the TKO? I noticed diagonal braces across the tunnel. I'm planning on a TKO 600 with a mid mount on the shifter. I too plan to modify the foot boxes.

[Rich A]

tirod,

Moving the engine forward on the roadster is not an easy as you might think.

The reason being is if you use the 4 port/pipe headers the body opening for the side pipe mounting flanges will need to be right at the rear seam of the front fender flare.
So you would have to modify or redesign the 4 port/pipe headers to make them exit in the correct body location.

Now using shorty headers aren't as bad, but will need to modify or redesign the J-pipes to make them exit in the correct body location.


The coupe/spyder is that bad it just involves cutting the exhaust body cut more forward.

[tirod]

I appreciate the caution about the headers, and hasten to add fuel to that fire. At the moment, under car exhaust is the preference - how the pipes run outside is a bit worry free in that regard. There will be other considerations - and the extra two inches might be very welcome.

We all have certain things we'd like to do, given time and ability. Moving the engine forward by simply flipping the mounts, no surgery or welding, is now much more likely. Mods necessary to have a more natural shifter location make sense, too. The forward leaning shifter, original or aftermarket, doesn't look well sorted out - more like a necessary evil.

Thanks for all the input, it nails down exactly how it can be done. Almost a no brainer in it's respect.

[stengun]

Howdy Thanatopsis,

Originally Posted by Thanatopsis

Paul,

Did that move interfere with the shifter on the TKO? I noticed diagonal braces across the tunnel. I'm planning on a TKO 600 with a mid mount on the shifter. I too plan to modify the foot boxes.

No, but my frame from just rear of the engine mounts is custom built and it is totally different the the original FFR frame.

I mount my shifter in the rear position and I currently have the FFR shifter handle attached but I'm probably going to either shorten it or use a different handle.

Cutting the exhaust openings another 1 1/2" isn't a problem.

Paul