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Of bolt in front axle conversions.

7647 Views 15 Replies 6 Participants Last post by  406Rich
Hello every-one.
As well as being Gasser Enthusiast I am also a 4wd Enthusiast and is common to convert IFS equipped trucks to solid axle´s.
Some of the kits used are BOLT in not weld in, I seem to remember this was also done with allot of gassers.
And in my home country (Australia see my introductory post for more info) the chassis strengthning kits used to convert 6 cylinder equipped cars to v8 power were originaly WELD in.
Till it was discovered that the new welds were actually tearing the floor metal out, even my late father an expert welder agreed that if you not a qualified welder then BOLT in is best, soooo my question is.
Are there any BOLT in kits still avaliable for straight axle conversions or will I have to make up my own???.
OK be back to see if I get any answers tomorrow. Peter.
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Welcome again Peter. On most of the cars that become gassers, they have full thicker metal frames to weld to. So they are pretty stout. But when you are building a unitbody car (no seperate frame) you need to reinforce the welded area. Just like roll bars/cages it requires you to sandwich steel plating top and bottom of the flooring. This disperses the stress across a larger area and saves the thinner metal. Anything is doable if done right. Mark L
Hello gain Mark and every-one.
UMMMMM interesting, but like I said I am basing my thoughts on the expierences with the uni-body enforcing kits used on the Australian Holden when converted to V8.
A bit of history.
See from 1948 till 1968 G.M.H Australia didnt offer a V8 and the 6 cylinder motors ranged from 132 cui to 186 cui, fairly small capacity.
ANYWAY, around 1966\67 the first V8 conversions took place and throughout the 1970´s to early 1980´s many were successfully converted, around late 1980 legislation began to clamp down and was decreed cars with no V8 option converted to V8 had to have full underbody re-inforcement.
Hence the sub fram strenghtning kits, as I said before these were first welded in however to the amazment of all the ëngineers¨the new welds flexed at different rates to the original metal and proceeded to tear out floors, this was when it was realized that BOLT in was best.
Even my late father who had ability to weld alloy and cast metals agreed that for capeable but un-qualified enthusiasts working at home BOLT in was the best way to go.
SO, though I can mig\electric weld if going the leaf front end way I will BOLT in.
Using insert tubes and crush tubes to prevent distortion, the nuts will be tightened using a proper torque wrenceh and then drilled and split-pined to stop them un-doing themselves.
OK now to see what the answer to my other question was, back soon Peter.
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Back in the late 60's I had a '57 Chev Belaire sedan that I wanted to gasser, but didn't have a welder at home. I did have a welder at work and could stick weld parts, but no way to weld them once I got them home. I decided to try and put a '55-'59 Chev truck axle under the front by making all my mounts as bolt in mounts. In the rear I made a channel shaped mount with the rear spring perch welded to it. Then cross drilled the frame and put 4 long throughbolts and nuts on them. I had predrilled the mounts I made, so once they were located on the frame I could simply drill through the holes from each side and put the bolts in place.
Did the same for the front spring perches. Since I couldn't stub the frame this was all done with the stock frame used. I put sheetmetal pieces over the old spring pockets to clean up the holes and hide them, and painted them black. For the steering I used the stock box and welded up a steering rod to attach to the stock steering box arm. At the backing plate I built a bolt on bracket to accept the rod I built. I removed my arm off the steering box and took it to work to heat and bend it for a little more drop.
Shock mounts were the stock truck mounts at the axle, but I built bolt on frame mounts for the top. It took mea week to do the swap, and I used '49-54 pass. car drums to convert the axle to 5x4.75" bolt pattern. I ended up with an axle that actually worked quite well, and could always be converted back to control arms if I ever tired of the straight axle. Never did, as I eventually sold it and moved to another project.
I did two more Tri 5 Chevys after that with axles, but had a welder then, and was able to weld mounts and weld them both in. It saves a lot of time and they are much easier that way! The Speedway axle in my 1946 Austin was very easy to install, and took much less time, even with a lot of frame work to strengthen the lightweight Austin frame!
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Maybe it would be better to build in a sub frame, that way you could use to bolt in engine/trans as for ideas...
Maybe it would be better to build in a sub frame, that way you could use to bolt in engine/trans as for ideas...
I actually think that's the best solution! Build it all up and squared off perfectly, then just rent or borrow a welder for the day and chop your frame off and weld it in. That makes much more sense!
UMMMMM thanks for all the suggestions.
Ummmmm I CAN mig\electric weld but have not for along time, plus to the rules in my home country are VERY strict and have almost eliminated home fabrication.
BUT - - - seems once my Cats and I settled in America I will be acquiring a nice little Mig Welder and a few other tools (new or 2nd hand what ARE prices for new Mig Weldrs???) getting some practise and then starting a project.
WISH I´d been able to take the 48\49 Studebaker I saw offered on another site last year was a coupe and complete and only $800 !!!.
Back soon and again THANKS for all the comments. Peter.
Just had nother look and YES I agree.
Build myself with welding is the best way to go.
UMMMMMM I could always consider a Ford Transverse fronnt end as well couldnt I???.
Back soon Peter.
...UMMMMMM I could always consider a Ford Transverse fronnt end as well couldnt I???...
There have been several with that mount. I thought about it for a while, even have one sitting outside the shop I was thinking of using. Here's an article that I was looking at for info.



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The next axle install I do will be a ford transverse spring and split bones or hairpins. This set up would be simple to do in a tri 5 on either the stock frame or a new stub
THANKS mt 94ss and Str8axle.
YES I think the Ford Transverse axle makes for a good conversion and recently (well 14 months or so ago) I remember in an American magazine - - - THINK was Custom Car Kulture (or simlar name) a genuine surviving 55 Chev Gasser with a transverse set up in front.
OK have dash might be back later or more probably Monday, THANKS AGAIN Peter.
Memory seems to be telling me about a BLAIRS SPEED SHOP???.
Located in California in the 1960´s.
ALSO that they supplied complete leaf front conversions ready to weld\bolt in???.
Back later. Peter.
If you can read the small print in the photos that I attached to the previous response, it states that 'Blair's chassis shop probably turns out one a week, usually Chevy's'. I'm sure that they did both, but the kit in the article is parallel leaf.

The transverse leaf spring is a simple one to install, and it works decently for a car that's not too heavy. They are not designed for cars that are heavier, as they allow a fair amount of body roll, even if you use coilover type shocks, which would be mandatory to stabilize a heavier car.
If your build car is under 3000 lbs. the transverse spring is good option, but I put one under my '40 Chevy coupe and it was a bit scarey if you made turns at freeway speeds. Lots of body roll, and rearend rolling back and forth as you continually corrected. With enough work they will work, but you have to really stiffen up everything to stabilize them in a car that size.
Thanks Austin, I forgot to mention that in my last post. You are right. Transverse spring is best suited to a light car.
Other than me I`m not sure anybody else is running transverse spring, but I`m nose down instead of up, I weigh in at 2570 lbs and I think its going to stay that way, it handles great, just looking thru some of the pics I see a few of the oldshots with transverse springs...


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