New PowerTrain Project

[Branch68]

Hi, I'm new to forum, but have been a frequent lurker for about a year. Last summer, I bought a 68’ swb stepside in very good shape. I have already been enjoying it and have completed a few good projects. However, it is going to get ‘serious’ soon and this will be more ambitious than many of my car projects. So, it’s a good time to get some other folks thoughts before I start spending money. I figure a thread to document and ask questions along the way might be a good thing. Here it goes!

Where I started

The truck was in pretty good shape when I got it. I’m guessing it was restored something like 10-15 years ago and two owners ago. It doesn’t appear to have been driven much, and looks like most of that time was spent covered. The paints not perfect, but she’s rust free. The most recent owner converted it to a manual Muncie 4 speed and gave the existing goodwrench engine the “quest” treatment. He also lowered it. I *think* it is lowered 4 inches all around. with spindles/springs in the front and blocks/springs in the back.

What I’ve already done

Since I’ve had it, I’ve fixed a lot of the little things (oil leaks, speedo, power-steering). The one big project I completed was to convert it to fuel injection. Here, I went the road less travelled. I built a megasquirt MS2 from a “build your own” kit. I soldered the board, built my own harness and fuse panel, sourced the sensors, and a NOS holley 950 cfm tbi unit on. Lots of learning/time, but I’m pretty happy with the result. I also now have the headroom for a much larger engine.

Where I would like to go

My lovely wife gave me a TKO600 kit from American powertrain as an anniversary present. When I install this, I’m thinking I’ll do a power-train upgrade front to back. My intent is to build it up to be a better street truck, with north of 500 hp. It doesn’t need to be full pro-turing or pro-street. Just a good fun ride that jumps when you stomp it and won’t scare you to death in a corner. I’m thinking I’ll build a SBC 400 that redlines somewhere around 6-6500rpm. I plan to keep a stock’ish suspension setup perhaps with simple mods to improve suspension geometry/handling/ride. It is also already lower in the front than I’d like, so I may replace the front drop springs to remove the rake.

First Question/Purchase

So, I’m thinking the first big thing I need to decide on is the rear-end. Should I upgrade the existing truck 12 bolt or upgrade to a ford 9”? I’ve done some looking at parts/prices. It looks like I could easily spend $1000-1500 for axles, ring, and a trutrac for the existing truck 12 bolt. If were to go with a ford 9, it looks like it is at least $2500 for a drop in by Strange. The first gear of the TKO600 is 2.87, and I doubt I would have either 4.11s or 3.73s to cruise at around 70 mph@2000rpm. So I’d have 6400-7000 ft-lbs on the axles.
Is the ford 9 worth the extra cash for my plans? I hear a lot of folks say the 12 bolt truck rearend is no good, but I haven’t seen any first-hand accounts of breakage much less any real data on power-level. Is there better places/prices to get a non-junk-yard ford 9?

[siggyfreud]

Welcome. Sounds like an awesome place to start and super cool that your wife got you that transmission!

On my project I chose to upgrade the existing 12bolt with better axles. But going to a Ford 9 is also a popular approach. I plan to run 500-650HP depending on the motor I put in. That said, the number of really hard launches it's going to see will be limited (not saying never though) so I'm not extremely worried about the rear holding up.

There are a lot of people running 700hp on a truck 12-bolt and living to tell about it.

I think things to consider to help keep it healthy though are strong axles, a cover that can add some pre-load to the bearing caps, and a good rear suspension setup that will keep the rear from bouncing under power. If you're bouncing it a lot under acceleration, that is where you're going to break something.

But I remember a lot of guys over on hotrodders.com running 600-700 through their truck 12-bolts, with upgrades, and doing fine.

[68Stepbed]

First off, Welcome to the board!

Second, you covered alot of ground in your first post, so I'll try to give advice in a condensed form.

Suspension: There's alot of options out there right now, but be sure to shop around and read real reviews and real world experience before jumping into something with the best price. Keep in mind there aren't many good option to improve geometry and handling that still utilize the stock crossmember. The Ridetech StreetGrip system would be about the only real option for keeping the stock crossmember. The next options would be a whole new bolt in suspension. There's only two options I'll recommend for improved handling and ride. 1) https://totalcostinvolved.com/produc...evy-c10-truck/ I have this in my 68, and I'm willing to answer any questions if you're interested. 2) http://nolimit.net/products#!/~/prod...32&id=26810473 Rob builds a nice product and stands behind it. I personally don't have his products, but I compete against a few that do. I'll only recommend these two because I've seen them in action and THEY WORK!! Yes, this all may seem way more expensive than some options, but I've done lots of research and I've learned that you get what you pay for. Stay away from Heidt's and CPP stuff.

Engine: I really don't need to say too much here, since you seem to have what you want sorted out. I do want to mention that an LS3 525 crate engine will have all the power you're after and will make that power consistently with great street manners. I know quite a few people with 500+hp 383 and 400s, and my 530hp LS1 has given me no fuss about idling and running in any condition while they're overheating and loading up and fouling plugs. Just my .02

Rearend: I've been beating and autocrossing on a 12 bolt with 500+ hp for a few years now with no issues. The only upgrade has been an Eaton LSD carrier. Yes, I'm still using stock axles and a used 4.11 R&P gearset. I may upgrade to Moser hubs and axles this winter, but my stock c-clip axles have held up well. Even if they break next event, I still can't complain. If you're just wanting a hefty street bruiser and not an all-out race truck, then going 9" may be overkill. However, a 9" is always a good investment, and has tons of aftermarket support.

[Branch68]

Thanks for the thoughts. I spent some time doing a real price out what an rebuild/upgrade to the 12 bolt would look like...it gets more expensive than I thought. I think the 9" is worth the extra money in "resale" value and that I can just swap it when the time comes. I'll post the specifics on what I buy/build, but the $2500 all in from Strange looks hard to beat.

Those suspension setups look pretty awesome, but that is a bit of sticker shock for me. I should mention the truck does already have aftermarket front control arms. I'm not 100% positive, but they look like these from western-chassis. Not sure if they are any good...I will say they don't seem lightweight.
https://westernchassisinc.com/1963-7...Arm-Set-Lower/
https://westernchassisinc.com/1963-7...ntrol-Arm-Set/

Step68, I hear you on the LS. I've definitely thought about it. Is the lack reliability on 383s and 400s because they are carb'd? I was hoping injection would add some drivability. If I went LS, I'd would have to scrap the injection that I just built, and add on some more costs like headers, and an MS3, etc. I'll probably push out that decision until I get the suspension and rear-end figured out. I'm definitely open to it, but there is a cost/enjoyment balance somewhere in there.

[68Stepbed]

Originally Posted by Branch68

Thanks for the thoughts. I spent some time doing a real price out what an rebuild/upgrade to the 12 bolt would look like...it gets more expensive than I thought. I think the 9" is worth the extra money in "resale" value and that I can just swap it when the time comes. I'll post the specifics on what I buy/build, but the $2500 all in from Strange looks hard to beat.

Those suspension setups look pretty awesome, but that is a bit of sticker shock for me. I should mention the truck does already have aftermarket front control arms. I'm not 100% positive, but they look like these from western-chassis. Not sure if they are any good...I will say they don't seem lightweight.
https://westernchassisinc.com/1963-7...Arm-Set-Lower/
https://westernchassisinc.com/1963-7...ntrol-Arm-Set/

Step68, I hear you on the LS. I've definitely thought about it. Is the lack reliability on 383s and 400s because they are carb'd? I was hoping injection would add some drivability. If I went LS, I'd would have to scrap the injection that I just built, and add on some more costs like headers, and an MS3, etc. I'll probably push out that decision until I get the suspension and rear-end figured out. I'm definitely open to it, but there is a cost/enjoyment balance somewhere in there.

I hear ya on the sticker shock on the suspension. It seems like quite a bit, but if you figure in the cost of rebuilding and replacing all the stock stuff, the cost isn't as far off as you think, it's just all in one lump sum instead of spreading out the costs. But, I do understand everybody has to stay in a budget.

As for the 383/400 engine issues, part of it is carb issues, others seem to be valvetrain issues. Once you get to a certain point of power, and cam lift/duration, valvetrain stability comes into play. My buddy has a 650+hp 427 sbc. Everytime he drives it, something tends to break. He finally got it somewhat dependable, but he has close to $30K in it at this point!

[Branch68]

Circling back to update the thread. I started this project by purchasing a frame stiffener. Summit had one for $999https://www.summitracing.com/parts/s...BoCkgcQAvD_BwE It has been a serious let down at every step of the way.

This kit comes with four bolt in boxing brackets (two forward, and two back). The front brackets were anything but bolt-in. 6 out of 8 bolt holes didn't line up. Talked to both Summit and then I found the actual vendor. The vendor seemed to be aware that this was a problem, but didn't offere to do much to fix it...and pretty much told me to drill my frame. The holes were off just enough that I had to weld up the old holes and then drill new ones. A royal pain, but I did it.

Then I hit the real challenge. Going to bolt this in, it will not clear the floor pan. It looks like its at least an inch too tall to fit under the cab. Anybody have advice here? I'm at a crossroads, send it back, modify it? Am I missing something?