Inliners International Forums General Discussion Engines 250 Frame mounts

OK so I finally got my block mounts that I needed, and I am ready to install the engine on Sat. I figured why not use the 6 cyl frame brackets that locdoc sent me since they are already cleaned and painted. When I pulled the old 350 ones off I see that they are slightly different and the 350 brackets go in the front two holes and these 6 cyl brackets go in the rear two holes on the frame. The problem is that when I measure from the back of the engine up, and from the bell housing of the tranny up, we are talking 16 inches exactly for both, and the motor mounts on the engine are lining up perfectly with the original 350 mounts in the front two holes! What gives? Is it a problem to used those?

The only thing I can think of is that maybe everything will have to slide back for fan clearance, I haven't measured to the front of the engine yet... I guess it's no big deal to slide the tranny crossmember back, I am just wanting to know WHY and if I really need to at all now... I have seen where people say you need to use the different brackets and move the engine, but mine seems to be forcing me to use the existing stuff, wierd...

A 250 was a stock engine in your '71 so you should really have no trouble mounting it.The frame is the same whether it was delivered with a 6 or 8.The 6 C10 I had in the past did have a rather thin radiator with the water pump having an extension to place the fan closer to the radiator.Maybe the V8's are different and you might have to adjust your radiator forward.

I just remembered that I will have to cut the driveshaft too, so I definitely don't want to move everything back if I don't have to, any insight would be apriciated. Putting a 73 250 in a 71 Chevy Truck.

Drew is correct. Adding to that would be that the center motor mount bolt hole in the block is exactly the same distance from the back of the block on both the 250 and the V8 so the tranny position does not move. On the 6 this is the top bolt hole and on the V8 it is the bottom bolt hole. I would attach the upper mounts to the 250 and then add the lower mounts to them with the through bolts and lower it all into the frame. The lower mounts should line up with the holes in the front crossmember when the engine is back against the bellhousing. Now you know which set of holes to use. It is possible they might be off forward or backward by a fraction of an inch and that can be adjusted by loosening the tranny mount on its crossmember so it can slide as needed. The driveshaft yoke will accept this slight movement without any problem.

If the lower mounts are way off relative to the crossmember holes then something is wrong. They might be for a different chassis.

I don't want to cloud the issue here but,Although both the inline's and the V8s engine mount bolt holes (on the engine)may position the mount the same be it an 8 or 6, there can still be a difference. I don't know about a C-10 pickup for sure but on a 68 to mid 70's Nova the "frame bracket" that the engine mounts bolt to are different. What I mean is , the piece that bolts to the frame crossmember for a 6 cylinder is NOT the same as the one that bolts to the crossmember for the 8.Whether or not this is the case with a C-10 pickup I don't know for certain but its worth checking to be sure.Having the wrong piece for the crossmember will definately change where your engine sits in relation to the rad and bell housing .

Yes they are different. My initial question was that I already have some different 6 cyl frame mounts, and I was trying to decide if I need to use them since the measurements line up to the existing V8 Frame brackets.

Also, when I lay them in place, they can only go into a specific place on the frame by the way the bolt holes line up, you can't mix them up. The 6 cyl brackets must go in the rear holes, and the V8 brackets must go in the front holes in the frame.

So anyway... I measured to the front of the engine and it looks like it will just barely clear the radiator with the fan on with 1" clearance which will be just fine if it works that way in-reality once it's in place.

With this possibility, I have decided to start with using the V8 brackets installed and set the engine in place and see what my clearances are to the radiator, if it works, then great... If it's too close, I'll just yank the driveshaft, swap out the brackets to the 6 cyl ones while it's hanging there, and slide everything back the three inches, and drop it down onto the new frame brackets. The brackets are real easy to swap out so it shouldn't be too much of a delay if it doesn't work, but will save me $50 at the driveshaft shop if it does work!

So that's the plan for Sat! I'll post the results if anyone is interested. This is a great learning experience, but not many people, if anyone swap from a V8 to an inline 6 in these trucks so it might not be a well sought after FAQ haha...

I don't think anyone, including me, meant to imply the 6 and 8 brackets were the same. It just shouldn't be a major problem since the 250 was a standard engine for that truck and should drop in easily with no problems with the right brackets. Before visiting a drive shaft shop, I would scour local dismantling yards. Those driveshafts are plentyful.

Drew, I was replying to Nortin who didn't see that I already had both sets in my possesion. I know it's not a major problem, I was just looking for someone with experience with the two brackets, I will find out soon enough.

My truck has been shortened to a five foot bed, it's very short, so this is not a stock driveshaft.

Walt, no need to take pics, thanks. I already have both sets and I'm sure one will work just fine. There would be something majorly wrong if I had to make a set of mounts.

71Stepside,
Yes,you do indicate a 5 foot bed. Sorry, should have paid closer attention. Did you do that bed? How was the frame handled?Never seen one done that way.Probably,cool. Couldn't find a pic on your homepage.Got any?

So you have a non stepside?
Looks cool!

Personally, I wouldn't have gone that short because he (don't know who) cut the fenders too not just the flat bed sides. I would have just removed the empty space in front and behind them because I have to finish the welding job!

It looks very cool though, reminds me of something you'd see in a ZZ top video haha...

They didn't do the frame the normal way either, and everyone told me not to buy it, but I couldn't beat the price, so I took a chance and it turned out good after I did a little fixing up on the rear end. Instead of cutting the frame like most people would, they cut the rear of the frame and then removed the Coil spring rear end and bolted and welded a leaf spring rear end in place about 18 inches forward. They did a redneck C notch which is on my list to correct, but it works fine for now, and better once I add another leaf spring. Here's a pic and my build site:
71Stepside

i removed a 327 from a 63 truck and the motor mount perches that mount to the frame were in the rear holes in the frame? do some v8's use the front holes too. i am installing a 292 in mine and needed to get different ones for pass side. the perches that fit in the front holes are made a little different, they come foward a little and the bottom mount hole is closer to the frame. i am wondering if those front mounting perches you are talking about will fit the 292? how many different ones did chevrolet make for these trucks? just asking if anyone knows. thanks

Here's some pics of interest. My engine as of the work I completed tonight:



So I did a final put together and my bolt up fan bangs against the crank and thermostat housing, when I use a spare stock fan, it works great but puts me over budget on the radiator when I do a final measurement. So I answer my own question and if anyone ever changes from a 6 to a 350 it won't matter and worst case you have to get a spacer for your fan to get closer to the radiator, but if you change from a 350 to an inline you must use the 6 cyl frame brackets and move the engine back for radiator clearance.

So thank you after all locdoc for the 6 cyl brackets. They weren't what I was looking for in the beginning, but something I needed in the end!

hoggyrubber, why do you need to replace the passenger side? Is it cracked or not lining up? The frame mounts may have changed in 67-72, from 63-66 I dunno... I know the block mounts were the same, I got mine off a 66 model, sorry I didn't notice what location the frame brackets were in, but come to think of it, the frame mounts were there, so if we decide that is what you need I can get it for you easy and cheap from that same truck. To answer your question yes, my V8 used the front holes, but you will need to use the rear holes for Rad clearance like me....

Just for the heck of it here is a pic with BOTH the 6cyl and the V8 Frame brackets installed in their correct locations at the same time. Note the different lower bolt location so there is no moving them around. This is looking at the passenger side so the left bracket is the V8 and the right is the 6 Cyl.

Thomas, I've never seen a "shorty" put together quite like that.A rough ride for sure. All the pics you are posting make better sense of your bracket work and will help as future reference for someone.

thanks for the extra pics they are great. i have several issues on mine. the drivers side is fine, i can use perch they were using which was in rear position, but this engine wasn't original. i also have a ample supply of brackets that mount to block for this too, >20. this is all same as my 250 i put in my 64. the pass side is different, i knew this going in with a 292. their motor mount goes in the front position and is offset from other one. i was told you could move it foward which is oviously wrong as displayed in your pics. also the bracket that bolts to engine has different bolt hole spacing the holes are closer together than the spacing on 230/250 brackets and on the 327 v8 that came out of this truck. so what i was wondering- #1 will the v8 perches like you have work on a 292 in the foward position, #2 is all 292 brackets that mount to block have closer bolt spacing like mine,can you only use a 292 bracket that bolts to block or will anything else work? mine is a 64 block and crank. just wondering for future reference.

I have perches for a V8 and a 250, I don't know if they are different for a 292 though, I hope there aren't THREE versions of these perches out there! I have zero experiece with 292's.

We need someone with a 63-66 and a 292 to take a pic of their passenger side bracket to see what it looks like and where it is eh?

Well, I got the engine in with no problems. I moved the crossmember and the tranny linkage bracket back 3 3/4" (the exact length from the V8 perch to the 6Cyl perch) and dropped the motor in and bolted it up. Everything looks good...