1960 BBC Swap

[TheBrewery]

Hey everyone,

So I am getting a great deal on a very low mile turn key BBC 402 with TH400 and some other parts for under $2k I know the 402 is kind of weak sauce for a BBC but it will get the 235 out and be a big improvement (I hope)

I have looked around here and there doesn't seem to be any 60 c10's with a BBC, 65+ has a ton of threads but I'm not sure if I can transfer that knowledge to the 60. The main thing is that to fit a BBC it requires you to trim the frame about ⅜" to fit the mounts and headers. The 65+ seem to all have C shaped frame rails, however mine is fully boxed. So I don't know if cutting them will cause any issues. Does anyone have any insight on this?

The plan is to drop in the 402 with a Muncie so I cant really move it too far forward without messing with the shifter location. I am trying to see if possibly I could use the front mounts but that seems like it would cause problems with the exhaust due to the trans mount not being able to be moved to the rear.

Sorry for all the ramble, Any comments are appreciated.

Mike

[Captainfab]

I do not know of any simply solution for engine mounts to install a big block into a '60-'62 frame. Are you trying to stay with a crossmember mounted bellhousing? If so, you will have to modify the firewall. If you cut the bellhousing crossmember out and go with a rear trans crossmember, you can move the engine forward to clear the firewall. You will have to fabricate a trans crossmember to fit into the X member. You might try using the '67-'72 small block engine mount brackets as I recommend for small blocks, but keep in mind that those engine mounts are not strong at all. The '73+ engine mounts are far superior but you will have to do some cutting and welding to make those work.

[TheBrewery]

Just the man I was hoping to hear from I’m not afraid of cutting and welding I just want to make sure I don’t compromise the frame in do so. CPP has some big block mounts that I have seen you mention in other posts do you think those would work?

I was planning on dropping the current trans crossmember and adding one at the tail.

On the frame modification, would opening up the box (making it a c) and adding gussets keep the strength?

Also considering using a motor plate but don’t think I want to live with the vibration.

[Captainfab]

None of the aftermarket universal engine mount brackets are going to fit the '60-'62 frame correctly without modification. The '60-'62 frame is shorter in height than the '63+ frames. That may work to your advantage when it comes to exhaust manifolds/headers. I wouldn't go cutting on the frame just yet.

Since you have the ability to cut and weld, I would just get a set of the '73+ engine mount brackets, mounts and clamshells. Get the engine and trans sitting in place, forward enough to clear the firewall. Then cut the top of the engine mount brackets down to level with the top of the frame and weld a piece on the top to reach the frame. Are you keeping the torsion bar front suspension?

[TheBrewery]

That sounds like a plan!

Yes I am planning to keep the torsion bars, I have not checked if they can handle the weight of the BBC but I assume that they should be able to just won't load the truck down with anything heavy

Could I not just shim up the frame to meet the bracket and weld the shim in place?

[ForgotUsername]

I put a 396 and rebuilt TH400 in my 1965 shortbed, it's a 1968 pickup 396 310 HP, got all this from a 1974 454 Chevy pickup, emissions tag said 454, so I assumed it was a 454.

Maybe the 454 was blown up and someone put in the 1968 pickup 396 engine.

I'm sorry but this was a waste of my time, I'm not happy with the big block and TH400, not that fast, no overdrive with 3.73 gears pretty much horrible on freeway.

I dream of putting in a 5.3 vortec engine with the fuel injection and a 4l60-e or even a T56 for better mpg.

I used 1974 motor mount stands, had to trim tops of frame rails to get them to fit(BBC wider) had to put BBC CPP front springs, barely touch brakes and the pickup did a nosedive.

Did you already buy the 402 and TH400?

[TheBrewery]

Originally Posted by ForgotUsername

I put a 396 and rebuilt TH400 in my 1965 shortbed, it's a 1968 pickup 396 310 HP, got all this from a 1974 454 Chevy pickup, emissions tag said 454, so I assumed it was a 454.

Maybe the 454 was blown up and someone put in the 1968 pickup 396 engine.

I'm sorry but this was a waste of my time, I'm not happy with the big block and TH400, not that fast, no overdrive with 3.73 gears pretty much horrible on freeway.

I dream of putting in a 5.3 vortec engine with the fuel injection and a 4l60-e or even a T56 for better mpg.

I used 1974 motor mount stands, had to trim tops of frame rails to get them to fit(BBC wider) had to put BBC CPP front springs, barely touch brakes and the pickup did a nosedive.

Did you already buy the 402 and TH400?

No I don't have the motor yet, It's currently in a Chevelle and will be pulled soon for an LS swap.

I think anything will be better than the 235 thats in it now, even a 8:1 402 I will be building the motor in the winter, but I think it will be fine for now. I will only really ever drive it to car shows and maybe a random trip to Home Depot, but where I live all the speed limits are 45 event the highway is 55 so I should be fine with the 1:1 final gear. If I need to take it farther I have a Durango with AC, a radio, and 18' trailer

[ForgotUsername]

Oh ok. At least there is plenty of room for Big Block in these trucks.

[Captainfab]

Yes if you don't mind how that looks.

Originally Posted by TheBrewery

That sounds like a plan!

Yes I am planning to keep the torsion bars, I have not checked if they can handle the weight of the BBC but I assume that they should be able to just won't load the truck down with anything heavy

Could I not just shim up the frame to meet the bracket and weld the shim in place?

[TheBrewery]

Hey captianfab, could you give me some advice on where to get the 73+ mounts? I have searched for them but all I can find are the part that attaches to the engine, not the "stands" that mount to the frame.

Thanks!

[Captainfab]

You'll have to find a used set in either a wrecking yard, craigslist, ebay, or here on the forum in the '73-'87 classifieds. I forgot to mention that you can also use a set of the '68-'71 big block engine mounts and frame brackets. That is if you can find the frame brackets. The engine mounts can be sorced from the aftermarket but they aren't cheap.

Originally Posted by TheBrewery

Hey captianfab, could you give me some advice on where to get the 73+ mounts? I have searched for them but all I can find are the part that attaches to the engine, not the "stands" that mount to the frame.

Thanks!

[TheBrewery]

Are these the right ones?

[Robert Haas]

Originally Posted by TheBrewery

Are these the right ones?

one is.






the other is a left

[Captainfab]

Those are the '68-'71 big block engine mount frame brackets.

Here are the correct '68-'71 big block engine mounts.

http://www.manestruckparts.com/store...Category_ID=16

You could use the standard I6/small block engine mounts but they won't hold up very well.

[TheBrewery]

Originally Posted by Captainfab

Those are the '68-'71 big block engine mount frame brackets.

Here are the correct '68-'71 big block engine mounts.

http://www.manestruckparts.com/store...Category_ID=16

You could use the standard I6/small block engine mounts but they won't hold up very well.

Thanks, I will pick up a set and see how they fit.

[TheBrewery]

I finally picked up the BBC, and am going to modify the mounts this weekend.

Here are some progress pics.





Wasnt really enough room to work so we pulled the front clip...



Also, cut out the cross member which was fun as the torsion bars are right there and the blades kept getting too close...



Next up is to position the mounts and fit them to my frame. I have two options, shim them up like this...


or cut them down so that the tops sit flush, I think to do that I would cut the bottom of them as they seem to be vertical and easy to put back together. However my question is would this put the motor too low?

Photo for reference


Edit: The images are tiny, here is a link to the album so you can zoom if you want. https://imgur.com/a/hjIlZ

Thanks,
Mike

[SkinnyG]

Originally Posted by Robert Haas

one is.

the other is a left

Nobody else commented, but you, sir, are awesome!

[The Rocknrod]

Originally Posted by SkinnyG

Nobody else commented, but you, sir, are awesome!

Ya I laughed yesterday when I read it.

[350TacoZilla]

I cant add anything here for tech help but I will say the 402's aren't a bad motor. I had one in my 79 k10 and it had enough power for normal truck uses and still ran 14.7 in quarter @ 92mph if memory is correct. The small oval port heads and low compression they usually have means they run on even low octane fuel and are decent on MPG for a big block.

Going with the muncie is a good choice with that motor also, the TH400's are great transmissions for reliability even in rough service vehicles or big power but they really suck HP to spin.

[TheBrewery]

CaptainFab, Thanks it is lowered and I don't want it to hit so shims it will be.

Does anyone know the correct direction? I had them the other way with the bottom going towards the cab and it was off the crossmember when back far enough to clear the radiator.

And with them pointing towards the front they look like they are wrong...



Thanks,

Mike

[Captainfab]

The way you are installing the engine mount brackets, it really doesn't matter since you will be drilling new holes. When installed in a '63-'72 frame, IIRC the bottom leg goes towards the rear utilizing the factory holes.

Originally Posted by TheBrewery

CaptainFab, Thanks it is lowered and I don't want it to hit so shims it will be.

Does anyone know the correct direction? I had them the other way with the bottom going towards the cab and it was off the crossmember when back far enough to clear the radiator.

And with them pointing towards the front they look like they are wrong...

Thanks,

Mike

If the heads on this 402 are the 820 castings, those are actually good flowing heads.

[TheBrewery]

Originally Posted by Captainfab

The way you are installing the engine mount brackets, it really doesn't matter since you will be drilling new holes. When installed in a '63-'72 frame, IIRC the bottom leg goes towards the rear utilizing the factory holes.

Thanks, I will be burning them in soon and wanted to make sure I wasn't making a huge mistake.

Originally Posted by Captainfab

If the heads on this 402 are the 820 castings, those are actually good flowing heads.

They are the 6272292 casting from 72, the math on these comes out to 7.5:1 with the .125" or 5.5cc dome pistons. I have a line on some old bathtub chamber heads that drop the combustion chamber volume by 15cc's and add some quench. I'll be putting some work into them so hopefully they will make some better power...

[TheBrewery]

Originally Posted by 350TacoZilla

I cant add anything here for tech help but I will say the 402's aren't a bad motor. I had one in my 79 k10 and it had enough power for normal truck uses and still ran 14.7 in quarter @ 92mph if memory is correct. The small oval port heads and low compression they usually have means they run on even low octane fuel and are decent on MPG for a big block.

Going with the muncie is a good choice with that motor also, the TH400's are great transmissions for reliability even in rough service vehicles or big power but they really suck HP to spin.

I have some better heads in the works to wake it up a bit, the factory 230hp from 1972 is not the best so some heads from a 68 396 should make a little more compression and thus more HP. I also have a th400 but will be backing this with a M20 Muncie. Also going to be running the stock eaton rear for a little bit until I get the 12 bolt built.

[350TacoZilla]

Yeah I got a bit luckier than that and had one from a 70 monte carlo. Actually still have the motor on stand 16 years after selling truck. According to the net it looks like it should have been 330hp-410ft.lbs in stock form and mine just had aluminum intake and headers. Before swapping that in the truck had a stock 350 4brl in it so the 402 was a big improvement at time and actually picked up 1-2 mpg using same Q-jet, the 350 was pretty tired though.

For gearing if you want better highway rpm you might consider getting a m21y gearset and swapping it in. I thought about trying the M21Y in my Chevelle but ended up going to a T5 since I found one for decent price.

[TheBrewery]

Originally Posted by 350TacoZilla

Yeah I got a bit luckier than that and had one from a 70 monte carlo. Actually still have the motor on stand 16 years after selling truck. According to the net it looks like it should have been 330hp-410ft.lbs in stock form and mine just had aluminum intake and headers. Before swapping that in the truck had a stock 350 4brl in it so the 402 was a big improvement at time and actually picked up 1-2 mpg using same Q-jet, the 350 was pretty tired though.

For gearing if you want better highway rpm you might consider getting a m21y gearset and swapping it in. I thought about trying the M21Y in my Chevelle but ended up going to a T5 since I found one for decent price.

Not super worried about MPG's as the speed limit here is 45 almost everywhere I would go, even the freeways are 55 so won't be spinning too fast(I think anyways). The plan is to swap a 4.11 12 bolt in soon which will make it more interesting.

I have 5 Muncies sitting in the garage to rebuild so maybe one will be a cruising tranny, I did a quick google but couldn't fine the m21y gears do you have a link? Also one for sure is going to get the m23z gears for some nasty burnouts