I6 to 350 swap questions

[dropdprpls10]

i have a I6 in my truck that i want to put a 350 that i have sitting in my garage.. is there a special motor mount i need to put the 350 in?? please PM me if you have any info for me !! thank you.....also the inline 6 needs a home its for free.. someone can just have it!

[Tx Firefighter]

It's really a shame that the search is disabled. This is a popular swap and it's been covered pretty detailed before.

Basically though, you can reuse the 6 cyllinder engine mounts if you wish. Also, the flywheel and starter from the 6 cylinder will bolt on to the new 350 as long as it's an 87 or earlier engine. The transmission will bolt right up also. GM used the same bellhousing pattern for both engines.

The factory V8 trucks did have different engine mounts. These mounts moved the engine several inches forward of where the 6 cylinder went. If you do decide to use the factory V8 mounts, you must beware that you will have to move your transmission forward the several inches too, which will require lengthening the driveshaft.

The easiest way is to put the 350 onto the factory 6 cylinder mounts. That way, the transmission stays right where it was stock and there are no mods needed to driveshaft either that way. The only downside to this method is that the distributor is somewhat close to the firewall. It doesn't hit, and there's no need for any special tricks, but it is closer. You can still adjust the timing and remove the distributor if you ever needed too.

Some folks will tell you to put in a bigger radiator. I'll say, try it first. I live in Texas, where it gets above 100 degrees regularly, and I've always reused the 6 cylinder radiators with the new V8 with no overheating troubles. I feel that in your climate, you certainly won't have any issues with overheating. Look at it this way, if it works, your ahead the 150 bucks that the bigger V8 radiator would have cost. If it overheats, well at least you tried.

You will also have to lengthen the steel accelerator pedal rod several inches to reach the V8 carburetor.

[dropdprpls10]

thank you for your info on this.. that is exactly what i was hoping to get... i didnt even know there was a search feature on this fourm.. im still kinda new to the site and new to building classics..thank you once again!!

[Longhorn Man]

On the putting it in the inline motor mount towers...that only works if it is a 250 engine. If it is a 292 then the mounts are staggared with one in the small block location, and the towers do not match either.

[super-k]

If tour truck had a 3spd manual behind that 250 and you are planning to put an automatic behind the V8,the speedo cable will be too long and will most likely bind and break.Also,the shift-linkage will need to be longer.It`s best to set the engine in the V8 position and make a longer driveshaft.The automatics used 2pc/manuals 1pc.You will need aprox.2"longer 1pc(if truck was 3spd.

[dropdprpls10]

im planning on putting a 700r4 behind the 350 i have a th 350 right now but i want to put an overdrive tranny in it.. so i was planning on replacing the speedo cable and other linkages anywho!! but this info helps alot too. ill have to go look and see which motor is in it the 250 or 292

[Tx Firefighter]

Just loosen the clamps that secure the speedo cable to the truck and take some slack out of it. I've done plenty of 3 speed to auto trans swaps and I've never changed a speedo cable yet. The truck I drive right now is a perfect example.

[dropdprpls10]

i just went out and looked at the i 6 mounts.. it looks like theres a block side and a frame side to them with a rubber plate in the middle!! now does the 350 block sit right on the frame side "towers" or do i need to put a mount on the block to mount it??

[Tx Firefighter]

You don't use the block side metal deal. You leave the bracket bolted to the frame and the rubber part in the middle bolts directly to the V8 block with three bolts.

The V8 doesn't have a block side metal part like the 6 cylinder does. That's only used to make up the gap because the I6 is much narrower than the V8 is.

[dropdprpls10]

awesome !! i should have the i 6 out this week! im guessing i should replace the rubber before i put the v-8 in!? hopefully i can get this 350 in soon!! thank you for your help!