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engine swaps

Posted By: DaveMcK38

engine swaps - Mon May 06 2019 03:12 AM

Originally set the 38 up for a 350 small block and 350 auto. Was wondering how much difference there is between the 350 and a 250 in line motor mount placement. Just wondering if I'll have start from scratch making new mount brackets or if the present ones are close?? Also how much difference is there in size ( mostly length) between the 250 and the original 216??
Thanks Dave
Posted By: Hotrod Lincoln

Re: engine swaps - Mon May 06 2019 04:40 AM

I believe the motor mount position on the 230/250 engines and the V8's are identical. The 292 has offset mounts with the passenger's side mount about 3 inches ahead of the driver's side, but the two smaller engines (as well as the 194, I believe) share the same mount position and bellhousing shape as the V8's.
Jerry
Posted By: DaveMcK38

Re: engine swaps - Mon May 13 2019 03:39 AM

Thanks Jerry, that helps. Any idea if the lengths are close to the same between the old motors and the newer versions?? Or could anybody point me to dimension specs on the chevy inlines over the years?
Posted By: Volfandt

Re: engine swaps - Mon May 13 2019 06:02 PM

Dave, alittle over a year ago did the opposite of what you're attempting in a 49 GMC. The GMC is similar to the Chevy except the GMC's had longer engines by a couple inches (like the more modern 230/250/292) so GMC engineered the radiator further towards the front for clearance.
In this video you can see how much room a 79 250 takes up in a 49 GMC 1/2 ton. If you look at how the radiator is mounted you'll see the difference between how GMC mounts the radiator further forward compared to the Chevy radiator mounting. The engine is too low and too close in the GMC for either a clutch fan of flex type fan and a std fan would have hit the bottom front cross member. The previous owner had an electric puller fan that just fit.

These pics show how the 250 is mounted in the GMC frame.
Pic 1
Pic 2

The mounts are stock Chevy clam shell type and the bottom mounts that were bolted to the welded on perches also lined up perfectly for the 350 engine I swapped in.
The difference was the upper mounts that bolted to the engine block.

If I read you post right it appears you already have the mounts installed in the frame for a SBC. If so you should be able to bolt a 230 or 250 to those lower mounts with the correct L6 upper mounts. A 292 uses and offset lower mount.
You'll just have to resolve the waterpump to radiator clearance which would seem to entail mounting the radiator alittle further forward.
Good luck
Dave
Posted By: DaveMcK38

Re: engine swaps - Tue May 14 2019 03:26 AM

So if I'm understanding this you are saying the 250 is actually a little longer than the older Chevy motors like the original 38 216??
I was pretty much planning on using an electric fan anyway probably a pusher in front. I'm not too far along with this project so nothing is really set in stone yet.
This thing was a real rust bucket sheet metal wise, if I can get the cab back up to decent shape then I'll keep going with it. Its basically a long term retirement project. My sheet metal fab and welding skills have been improving, so its getting a little easier the more I do.
Thanks, Dave
Posted By: EdPruss

Re: engine swaps - Tue May 14 2019 11:27 AM

Sucking fans mounted behind the radiator are more efficient, if there is room. The fan that goes with the 250 would make for a simpler installation, if it fits.

Ed
Posted By: Volfandt

Re: engine swaps - Tue May 14 2019 11:52 AM

Originally Posted by DaveMcK38
So if I'm understanding this you are saying the 250 is actually a little longer than the older Chevy motors like the original 38 216??

Thanks, Dave


Yes...
The GMC L6's were longer than the Chevy Stovebolt engine's by an inch or two (or maybe even alittle more). Someone once posted the spec's here once upon a time.
The 230/250/292 engines are also longer than the older Stovebolt L6's.

GMC mounted the radiator further forward to make the necessary clearance. One of the few frame differences between the AD GMC's & Chevy's were the front frame cross member and the radiator support on the GMC.

I never researched enough into what it would take to adapt a newer Chevy L6 in an older Chevy AD frame but if I were to start I'd look at the possibility into adapting a GMC AD radiator with it's set-back mounting bracketry into a Chevy radiator support frame and go from there. Could be an easy way to gain some needed clearance, perhaps.....

Good luck
Dave
Posted By: DaveMcK38

Re: engine swaps - Wed May 15 2019 02:16 PM

Just trying to get an idea if I'll need to massage the fire wall in order to set the motor back a bit. I guess I should just find a motor and plop it in.
I guess I was just hoping the newer versions were the same or shorter than the originals.
Posted By: Jay Zed

Re: engine swaps - Sun May 19 2019 12:53 AM

Originally Posted by EdPruss
Sucking fans mounted behind the radiator are more efficient, if there is room. The fan that goes with the 250 would make for a simpler installation, if it fits.

Ed


Ha ha, fans are pushers and pullers, not blowers and suckers ;-)
Posted By: Hotrod Lincoln

Re: engine swaps - Sun May 19 2019 02:16 AM

Regardless of where they're mounted, electric fans suck! That's why they invented "fan" belts, right?
Jerry
Posted By: mick53

Re: engine swaps - Sun May 19 2019 04:30 AM

My 292 is about 3" longer than my 235. I have been told with the radiator moved to the front of the stock mount and electric fan they will fit. I have to move mine back about 7 1/2" so I'm not sure.
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