And so it begins! 318 Poly to 360 LA Swap

[deppmobile]

After a couple of years getting everything together, I've finally taken spanner to car! 

A very tired 318 Poly will be coming out in a couple of weeks, to have the rebuilt 360 trial fitted to check engine mounts, headers, exhaust connections etc. That then comes out again to for final assembly, and the engine bay gets freshened up. And then in it goes again!

I bought the 360 as a rebuilt long block, but hadn't realised how tough it would be to get all the bits needed for the swap (unless you want to chuck £££££s at it.) Still haven't got everything sorted, but getting there.

The plan is to post a few pics as I go along (if I remember!) Wish me luck!

[cadboy]

Good luck

[Pete]

I imagine the engine mounts will be different, so there will be lots of mocking up to do, etc.

I quite like Polys - they are very robust - but parts availability is the killer, especially inlet manifolds...

I will be following this swap with great interest!!!

[graham fury]

hi I run a 66 fury with a poly engine have you any thoughts on what your going to do with the old poly

[deppmobile]

Apparently the poly mounts can be made to work by swapping sides and shimming, but the proof will be in the pudding!

I'm lucky that the poly already has a Weiand intake manifold and decent headers, so that is a big expense avoided, but rebuild parts are dear. Plan is to rebuild it and maybe stroke it, but need to see how bad it is first.

There's quite a following for the Poly now, and so many were ripped out and dumped they're getting rarer. I like the underdog, so plan will be for it to go back in - some day!

[Blue]

The thing that rules the poly out for me apart from the rarity and cost of parts is the weight. Big block weight with small block capacity doesn't sound like an ideal place to start from. Pound for pound (£ as well as lb) a stroked 360 is a great option these days.

[deppmobile]

I have to agree there, Blue

But I rarely apply logic when old cars are involved!

[mygasser]

and don't forget you can fit a 4" stroker in the poly the same as an la small block to make it a 390. kind of offsets the weight issue i reckon.
neil.

[deppmobile]

Much as I am nostalgic for the Poly, I'm still very interested to see what a rebuilt 360 will drive like compared to the very tired 318

Might need some disc brakes

[Dave999]

yeah the 4 inch bore in a poly seemingly works well if the block has thick walls to the cylinders

the cylinder spacing is certainly supposed to be big enough to achieve it

90 thou bore seen it done on hemi 6 so i'm sure the poly has enough meat.

https://www.hotrod.com/articles/mopp-01 ... ore-power/

how to make a 402 with a 4 inch bore and 4 inch stroker crank and some 360 rods...
if it weighs the same as a 400 or 383 might be a good thing
if it weighs more...mMmmmm

semi hemi head..........much like my own hemi 6...which came out of the quest in the US to turn Poly era HEAVY engines into modern light weight engines

hemi 6 and LA small blocks were the first Light weight thin wall cast Iron cylinder Blocks that chrysler did in the early/middle 60s LA v8 to replace A V8 hemi 6 to replace slant 6 as their thick walled ally block 225 had failed, due to daft fellas using the wrong antifreeze

hemi 6 kept the poly style top 3rd of a sphere shaped chamber and horrible rope rear main seal, and the LA got wedge heads and more investment.

hemi 6 went on to be NOT used by anyone apart from aussies although they had the factory built at chrysler US's expense with a capacity to supply all slant 6 and some LA markets with hemi 6 and 318/340 (USA south america, SA, AUS, spain, Belgium) Chrysler US got cold feet. factory became a completely unprofitable white elephant that ultimately resulted in a takeover by Mitsubishi

LA V8 engine became the norm in the US and consequently everywhere else. nobody but grandma wanted a 6 cylinder apart from the aussies

think i'd like a poly i too like an expensive to build "why don't you get a proper v8 " style engine, so i appreciate where you are coming from

Dave

[deppmobile]

Mmmmm.....as soon as someone says you shouldn't I want to.....

More progress

[deppmobile]

And new 360 in!

The existing engine mounts will work with a bit of jiggery pokery, and the headers need to be in the engine bay before the engine goes in. And I remembered after 15 minutes of faffing that the steering tie rod actually goes through the header bank

Engine back out now to finalise pulley positioning, clean up the engine bay and replace some very crusty wiring on the bulkhead.

New jobs discovered 1) replace all the 3 year old ball joint rubber boots that have disintegrated 2) small bit of welding 3) thinking of having a go at rebuilding the 727

Anyone who's had experience of this swap or any of the other jobs, input welcome, thanks!

[MattH]

You make that look very simple!!

[Steve]

This is a great thread.....like watching an old hotrodding show on telly....love it (and the car)

[deppmobile]

You make that look very simple!!

Knackered tendons that made my hand blow up like a balloon would suggest not! An hour and a half on my back with my arm in the air and my hand snaking through the manifolds to remove three bolts.....

So on to pulley alignment - I need an 8mm crank pulley spacer. Anyone on here do laser cutting?

Thanks!