The Stovebolt Site Forums The Shop Area The HiPo Shop Small Block vs Long Block

Helloooooo Stovebolters -

First off, thanks for all the posts and info, I have been reading them for a couple of weeks now. I am new to this and have a '50 1/2 ton that needs everything - it didn't even roll very well when I pushed it into the garage with my other truck.

I have heard a lot of talk about small block vs big block when swapping to an 8 cylinder motor and I am wondering which is easier, does it make that much of a difference and how many modifications are required to cross-members/motor mounts?
It seems like there are a lot of resources for remanufactured big blocks on the web, but not so for small blocks. Since I need a new engine, any suggestions??

Thanks

Steve

[img]http://www.blissink.com/steves50withleaves.JPG[/img]

Welcome to the Stovebolt!

We need more hot rodders.

I'm surprised you report finding more info about a big-block swap than a small-block. I've not seen much on big-block swaps, even thought I'm planning one.

There are both engine and transmission crossmembers availble to mount your motor and transmission, regardless of your engine choice. Steering box/column interference will be a problem regardless of engine choice, more so though with a big block.

Why would you want a big block? If you don't have a compelling reason you should probably stick with a small block if not a six.

To be honest, I want whatever is easiest - I'm looking for around 275-300 HP and am figuring on a 350 or 327.
I have a friend with a welder (a friend indeed) so I need a motor tranny configuration that will not require so much of his time. Maybe they bolt in? I don't know - this is my first.
I am planning on putting in a Mustang II IFS from ChevyDuty.
There's currently a six cylinder motor in there now, but I don't think the thing has run in a few years. The PO got the truck from the reservation near Yakima and it still has Army insignia in faded paint on the doors - plus a couple bullet holes.
So it seems like there are crossmember and motor mount kits available for the small block?
Any experience or suggestions as to which kit or are they all about the same?
Also I am planning on going to the local auto parts store for the engine, any tips on what to ask for regarding performance options?

Thanks

Steve

I'm pretty sure ChevyDuty has the crossmembers you are looking for. If you don't need the power of the big block I'd go with a 350.

Lots of things to think about when choosing performance options. I like a reliable driver that can get out of its own way. Carburated V-8 does that quite well. If you just want a clean running motor I'd check the Chevy dealer for a Targetmaster. Won't cost much and should run solid for years. I have two of them.

Are you planning to run an automatic? What do you have in mind for a year end? If its stock your truck has a torque tube rear under it now.

Thanks Old Sub,

I'll look for the TargetMaster you mentioned. Ultimately, I'd like a daily driver with some performance, so I was thinking 4barrel carb and intake combo from Holley or Edelbrock but I still need to research that.
Got most of the body panels removed now, had to cut a lot of bolts which is taking me forever - but I have time. I'll post pics this weekend.
Definitely auto trans - I liked the TH400 or maybe the TH350 with overdrive - I want to not be turning 3500 RPMs on the freeway if possible.
The rear end was my next question. I have the stock rear end on it now but I would have to change it out if I change to a 350?
I was just looking at it wondering if I can use the same leaf springs and just place a different rear axle there? I have read that a camaro or nova rear works well, any experience using these?

Thanks

Steve

The TargetMaster is a good motor for a relatively stock one. But it should provide plenty of power for your truck. Just my own opinion, but I'd go with an Edelbrock 1406 carb and 2101 manifold if you're gonna go with the stock TargetMaster cam. Good bottom end, easy to install and "set it and forget it" adjustments on the carb. Well..unless ya like to fool with things.

I'm not sure what you mean by TH350 with overdrive, unless you mean adding a Gear Vendors' OD unit behind the TH350. If so, this ain't a bolt-in operation, nor is it an inexpensive way to go. The GV OD runs around $2k.

There are basically 2 OD transmissions that can be intsalled relatively easily: the TH200-4R and TH700R4. The choice between the 2 is a matter of great debate, but my preference is the TH200-4R. I like the gear spacing better and it's the same length as a TH350 or Powerglide, where the TH700 is 3.5 inches longer.

I don't have enough experience on the rear ends on the AD trucks...but if you go with a TH350, the stick rear end will give the same engine speed as the current trans, since both are 1:1 high gear setups. If you want to drop the rpms for cruising, then an overdrive or rear end (or gear) swap is called for. Or you could do like I do with my 64 (4:10 gears) and drive in the slow lane and wave to people as they pass.

Best of luck with it

I'd suggest staying with a small block - they fit easier / are lighter / and you can build them to 400 HP plus. There are many suppliers for mounts and various parts required.

Hey Thanks for all the replies - food for thought.

Last question (for now...)

Say I get small block 350 and the TH200-4R - can I keep the stock rear end?

The stock drive shaft could be modified at a local machine shop?

This is my first time through this so I just need to know what to ask for so I can get 'er done.

Much Appreciated,

Steve

Not easily. Your current rear is the torque tube type, and adapting that to a modern automatic transmission is a challenge and if anyone makes a kit to do it, I've never seen it.

I've got a '73 Chevelle rear under by '55 1st, which would be the same as your truck with one significant exception. My truck was open driveline from the factory. The Chevelle rear needed to have the coil spring brackets cut off, and spring perches welded on.

Even if you use a rear from a leaf spring car you'll most likely need to move the perches, so the process will be similar. Also the spring bolt that is used to locate the axle is not at the axle centerline on your truck. If you buy a set of Mopar perches (lots of guys suggest that) you'll need to drill a new set of holes to locate the axle. I've heard 1-1/2 to 2 inches forward of the stock hole, but if it were mine I'd experiment until I like how the axle fit in the wheel wells. Or venders sell a perch kit ($150 at ChevyDuty) that has the right holes drilled in them.

And then you'll need a driveshaft the right length. You can probably find one in a wrecking yard given enough time. I'd just have one built.

excellent

thank you

I have a few suggestions to toss in.
A decade or so ago, GM tuned port injection "TPI" was the big thing everybody HAD to have. Now with the excellent LT1, LT4, LS1, & LS6 fuelie options, not to mention the aftermarket Holley Stealth and Lingenfelter Superram systems, the TPI has almost become the "red-headed step child" and been kicked to the curb. You can pick one up for just a few hundred anymore and you'll enjoy phenomenal torque and excellent 20 mpg-ish gas mileage. I had a 355 in my Corvette (10:1 compression, Isky 270 Mega-cam, 650 Holley on a Wieand dual plane) and swapped it into my IROC-Z Camaro making only the TPI change.
I'd say torque improved by about 80 lb-ft at the loss of only 300 rpm on the top of the rev band. Plus I gained about 3 mpg mileage too. Besides that, it's a GREAT looking set up. Torque is definitely more important with these trucks anyway.

About your rear end, you don't have to get those spendy Ford 9" and GM 12-bolt rear ends...unless of course you score one cheap at a salvage yard. Any GM 10-bolt from most 70's era cars (especially the F-bodies) will do absolutely fine with a torquey 350. And you can score a 10-bolt really cheap, with posi and a taller gear ratio for better highway cruising.

And another option with the transmission is the good old reliable Muncie 4-on-the-floor. Unless you WANT to run an automatic.

Here's where I am at:

[img]http://www.blissink.com/50bodyoffmostly.JPG[/img]

I spent three "days" working on disassembly.
I have to put this on hold for a couple weeks as I head out of town.

Next up: Mustang II IFS, 10 bolt posi rear (thanks for the tip Hot Rod Dad)and prime and paint.

Wow. Cool. Only 3 days, huh?

The kid I bought my truck from in Wyoming didn't bother painting the frame and it needs it. But I won't bother until I put my 406 in it. At that time, I too, will have to disassemble the truck, and then I'm sure I'll have LOTS of work to do prepping the frame to paint. I might go the POR-15 route. It's expensive stuff, but much easier than sandblasting the whole thing.

I'll be probably installing a 1968 4x4 suspension with 3.73 front and rear axle ratios. It uses the same 8-lug pattern I have now, and I love my chrome wheels. I'd want to keep those.
The only thing is, his transmission with married transfer case has a Chevy V8 bolt pattern, so THAT will be when I have to drop some kind of V8 into it.

I suppose if my 406 isn't ready by then (I need to buy everything...I only have the block), then any old V8 I can get my hands on would do temporarily. Maybe I could look for a TPI 350 out of a late-80's Camaro/Firebird. 24 mpg with better torque than my 235 has.

Please keep posting pics of your project.

Three days? What took you so long?

Just kidding of course. Last time I wanted to break one down I got a mess of teenage kids to come over and help out. Actually I've done that twice, and each time in a single day we were able to get the body off and down to the frame.

If you did that by yourself, or even with just one guy helping with the heavy stuff, that's pretty impressive.

If you should run acoss one of these TPI setups (complete with ECU, harness and sensors) for a few hundred, please email me about it. I'd love to put one in my 80 El Camino.

Actually I had my brother come over, I said I wanted to "show him something".
He left 2 hours later with a sore back after helping get the cab off. I forgot to cut the parking brake thing (doh!) and until then it was very hard to get the cab off.
I got hold of some teens who do the import hotrod thing - you know the cars, usually Hondas, big muffler, sounds like a 40 MPH fart -
anyways they are going to help lift out the old engine and tranny, drop the rear end and front end.
By the way, I was trying to figure out how to totally disconnect the front leaf springs from the frame - I got the bolts on each side off up front but there is like a pin or something still holding the thing on? The rear of the front leaf springs look like they're mounted to a mount that's riveted onto the frame?
I ordered a shop manual and hope there are pictures.
I leave in the AM for a week or so for work, so the plan is to break it all down the following weekend.

Have a good week everyone.

I think you'll need to grind, torch or drill out a bunch of rivets to get those brackets off. And if you look at the front you'll seen a chunk of steel inside the frame that you don't need any more and its held on by more rivets.

InTheDoghouse50:
Like the guys said, the smallblock is the way to go if you don't wanna go with a Six. You will want to dump the old rear and torque tube ( Here\'s Mine when it came out.)I used a rear out of an 84 Monte and it turned out to be a little narrower than I wanted. It measured the same as the stock rear but unless your planning on running narrow tires then that's not what you want. Figure out what tire/wheel combo you plan on running and make sure you take that into account when selecting your rear. I ended up having to put negative offset reversed wheels on mine to get the tire size I wanted. It turns out I like the deep dish look that I ended up with but it was a little more $.
MONGO

PS..
Please post links to your pics like I did above instead of the embeded image method to help save the bolt the bandwidth.

Thanks for the tip Mongo-

yeah I'll have to think about wheels and tires, good point.
I know the Mustang II IFS has a five bolt pattern, I wonder if it will be a prob getting a five bolt rear to match?

The pics are actually hosted on my server, the post only contains a link so the bolt's servers shouldn't be getting pinged bandwidth for the images - regardless I am planning on creating a site with all my free time....
But anyways, I like ChucktheTruck's website - entertaining and informative.

Steve

Yeah, My M2 has 4.75 by 5 bolt pattern, it's common on many of the donor rears that are around should be no problem finding something that matches. The PO of my truck had the M2 installed but didn't get as far as the rear so for the first couple years I drove around with 2 spares. 5 bolt and 6 bolt.
MONGO

I've got a question. Why did GM use a torque tube instead of just a long driveshaft? Is that somehow stronger than a long driveshaft would be?

Unless they were in the Lounge when it was deleted, there should be several threads in the archives discussing the advantages/disadvantages of torque tub systems.