58 engine swap, six to eight...
 

Re: 58 engine swap, six to eight...
 

You will need something like this, then you can do it in a couple days, bolt in.

https://www.ebay.com/i/381918413652?chn=ps&dispItem=1

Re: 58 engine swap, six to eight...
 

55-59 trucks came factory with v8, it is very doable with the propper parts

need to find a v8 bellhousing, starter and motor mounts
uses the same bellhousing mounts as the I6 just need to find a 55-59 v8 truck or 55-57 car bellhousing
uses a starter that bolts to the bellhousing from same era v8 and a few wiring changes from the stomp starter
front mounts need holes drilled in the block (depending on year of motor) and are available at truck shops



front mounts

http://cdn.classictruck.com/images/p...30_L1_Main.jpg

rear bellhousing rubber

https://ssli.ebayimg.com/images/g/4g...~U~/s-l640.jpg

where the front mount bolt to block and x-member

http://67-72chevytrucks.com/vboard/a...1&d=1294640179

Re: 58 engine swap, six to eight...
 

Totally doable, but even with the 4 speed aren't you still a 1:1 ratio in 4th gear and running at high rpm's? Or are you just thinking the V8 can handle the abuse better?

Re: 58 engine swap, six to eight...
 

A simple differential gear set change to a more moderate ratio will solve your top speed problem. The 6 has plenty of torque!

Re: 58 engine swap, six to eight...
 

I put a 4:10 (or 4:11, I can't remember) in my 57 1 ton with a 235 and it helped but it's still a little weak on hills and 50 to 55 is about all it wants. It works ok for me but I plan to put a 283 in it some day when I have time. The 283 likes higher rpm's better than a 235.

Re: 58 engine swap, six to eight...
 

My main focus is to increase the top end to around 60-65. Generally, my top speed when towing is around 55 or so. However, I don't wish to have the motor screaming along at top revs for hours at a time. Our average commute to a Rallye or show is two to three hundred miles. This just doesn't seem to me to be an optimal situation with a heavy trailer on behind...

By the by;
I used to work at the Fallbrook Naval Weapons Depot. Loved Fallbrook!

Re: 58 engine swap, six to eight...
 

Yeah, for sure. I think you need to consider an overdrive trans or regear the dif. Even with the 4 spd you are still at a 1:1 ratio in 4th, so bottom line is your rpm will be the same. As you said screaming along for hours. I don't know what your rear end ratio is, but in my 66 C20 I have a 4:56 rear with a 5spd and 31" tires and I cruise 80mph at 2500rpm. My 58 has a 3:90 rear with 700r4 and 28" tires and it's about the same. I had considered replacing or regearing on my trucks but OD made a huge difference on both, so much that I didn't mess with the rear end yet. If I blow it up I'll deal with it then but so far so good.
https://www.ringpinion.com/calculators/Calc_RPM.aspx
You can use this calculator to see what changes to make to achieve your desired goal.

Re: 58 engine swap, six to eight...
 

things to ponder
-a v8 will give you the power you need but the rpm will stay the same at the given speed unless you swap out the rear end gears, the whole rear end, install an overdrive behind the trans or install an overdrive transmission.
-if you swap the engine you may want to also swap to a larger rad or one with another row of core tubes because it will likely make more heat than the stock 6. the original rad is likely in need of a flush either way, even if you don't do the engine swap
-if you were to do a swap you also need to factor in some cash for an exhaust system, rad hoses, the mounts that ogre talks about, some throttle linkage and choke cable linkage, a bit of wiring change ups including a starter button or new ign switch if you want the deluxe swap, depending on what your donor is from and how much can be used from the donor vehicle.
-along with that, think about driving down the road with single system brakes. that means the master cylinder has only one circuit to run all the brakes. if a hose ruptures or whatever happens then you lose ALL the brakes except the park brake, if that operates. with a trailer behind that could be bad news.
I suggest to do a complete and thorough run through of what you actually have and what you need to fix, if anything, to make it feasible to drive down the highway at 60 mph with a trailer behind you. check (or have a shop check) the front end properly by putting it up on blocks under the axle so you can check the kingpins without load on them, the tie rods and drag link, steering box, the brakes, hoses and lines, etc. next block it up under the frame so the suspension is hanging and check all the springs, spring pins and bushings/mounts and shocks, body mounts, deck mounts, floor etc. look for cracks in the frame and cross members, loose rivets, bent parts etc. check wiring, operation of all the accesories like window cranks and door latches, wiper motor, heater and fan, seat mechanicals and comfort, glass etc. then check the body for the usual rusty spots (it looks great in the pic but take a close look, be critical). make a list and go from there. there are kits available for power brakes and steering which would make it more fun to drive. end of the day it's your truck, and do what you like, but be safe with it. there's a whole lot of other people driving on the same roads who expect other drivers to be using something roadworthy.
how much weight do you plan to tow, what configuration of trailer, does it have operational brakes? do you see yourself backing the trailer around with standard steering?

Re: 58 engine swap, six to eight...
 

Follow along with what Ogre said and it should be pretty well a rather quick swap "IF" you have all the right parts.

That includes the New V8 Motor mounts for the front and the correct V8 bellhousing that will bolt to the crossmember under the bellhousing. If you don't have the correct cast iron bellhousing on the V8 now make sure that you get one with the hole that matches the bearing retainer you have on your trans. The earlier V8 bellhousings had a smaller hole for the later ones did and I can't off hand tell you what year the break was.

As far as an Overdrive trans that can come later if you see that you are still running out of gear on the flats. I've been thinking serously about putting one behind the 454 in my 77 Dualie but that is a spendy addition that I don't have in the budget no more than I use the truck right now.

I'd say that the guys who suggest keeping the six to do what your wife wants to do with it have never towed a loaded trailer across two states with a six cylinder. It's bad enough on the hills if the V8 doesn't have enough poop to get the job done.

Re: 58 engine swap, six to eight...
 

Re: 58 engine swap, six to eight...
 

where the front mount bolt to block and x-member

http://67-72chevytrucks.com/vboard/a...1&d=1294640179[/QUOTE]

That is my truck, I used 1/2" plate with grade 8 bolts thru the front cross member. One big one and smaller, I thing the large used a factory hole and I had to drill the smaller. My engine location was dictated by the front drive line length which gives enough clearance at the back of the block for removing the distributor and valve covers and accessing transmission bell housing bolts. I would recommend adding a restraint from the block to the frame because the stud mounts do let the block move quite a bit which can crack the aluminum bellhousings if you use the transmission mount.