318 Poly in an Early A Body?

-
Bob Watkins

Bob Watkins

Active Member
Joined
Oct 14, 2018
Messages
35
Reaction score
19
Location
Kent, OH
I'm considering buying a 318 poly to put in my 64 Barracuda, along with an A727 trans. I know the heads are a bit larger, but I'm hoping there's room. Any headaches or horror stories to report?
 
Bob Watkins said:
I'm considering buying a 318 poly to put in my 64 Barracuda, along with an A727 trans. I know the heads are a bit larger, but I'm hoping there's room. Any headaches or horror stories to report?
Click to expand...
FYI, with a LOT of first hand poly experiences, you're gonna have a time stuffing it in, especially around the steer shaft. it is actually wider than a 383 or a 440. And weighs nearly as much. You'll need bigger torsion bars. Also, if you have power steering and want to keep in, forget it with the poly in the early darts. I have an early B body with factory power steering and there's barely an 1/8th between the head and the power steering box.

Assuming that is a push button transmission, you'll have to be careful with the cable routing but you should be able to reuse the cables.

No matter what, you're looking at a very tight fit
 
With the engine, the cons out-weigh the pros... actually, I don't see any pros. Same with the transmission. 727 will be a total horepower robber for a small cube engine, in addition to a nightmare to install. You will need to do major surgery to get a 727 to fit in a narrow body. Like fklskv said, LA motors are more plentiful than the poly motors, and the same can be said about 904's vs 727s.
 
You will have to modify the trans tunnel for a 727, not worth it in mho. You are on your own with headers, and a 4 barrel intake is rare and expensive. Then there is the small rear wheel wells. Any LA/ Magnum if done right will make an early Cuda Fly. Even with the stock 273 HP exhaust and manifolds. From 273 to 360. I've had one for 45 years.
 
I was helping a friend swap a 340 into a 65 Dart back in the 70s and he happened to have a poly sitting in his garage. We were talking about how relatively simple the swap would be aside from exhaust when he said, "can you imagine trying to fit that thing in here?" pointing to the poly. Well, next thing you know he's wheeling the engine hoist over to the poly and we stuck it in the engine compartment to see. After some serious measuring and contemplating we determined that it would be a real mess to get it to fit and pulled it back out. He never wanted the poly installed to begin with so we may have been a little quick to pass judgement but it looked to be a fitment nightmare. A lot of hammering, cutting, fabricating, etc. As mentioned, a 383 or 440 is a lot easier.
 
66fs said:
You will have to modify the trans tunnel for a 727, not worth it in mho. You are on your own with headers, and a 4 barrel intake is rare and expensive. Then there is the small rear wheel wells. Any LA/ Magnum if done right will make an early Cuda Fly. Even with the stock 273 HP exhaust and manifolds. From 273 to 360. I've had one for 45 years.
Click to expand...
Actually headers are now being produced, they are expensive, TTI, CCP and a couple others, but they’re about a 1000.

Factory 4 barrels can be had as low as 350 to as high as 750.

Dual quads and even six pack manifolds can be had for now much more.

Wieland, CCP and a few smaller outfits are selling brand new, aluminum 4 barrel intakes for about 600.
gregpurcell said:
I'm wanting to say that the LA exhaust manifolds are not the same, so there's one more headache.
Click to expand...

They are not. Port spacing is entirely different.

But the factory manifolds are rear dump and “should” clear


HOWEVER,

Factory Ford Mustang 5.0 GT Headers will fit with a minor modification to the bolt hole locations. However, they are unlikely to fit in an Early A body with out so tube modifications. But can be had for less than 50 bucks.

Also, if one really wanted, an LS7 intake has the exact same port locations and nearly the same shape and size as the poly. So with a simple spaced plate, one can put an LS7 intake on a poly.


It can be done cheap if one thinks outside the box
 
A 331,354, 392 Hemi will fit, why not a Poly? I like the idea.
 
In an early a? Sure you could get it in there but gonna be tight. Plus poly stuff is stupid expensive. Not worth it to me. But go for it man.
 
It occurs to me that, with the money you're talking to install an antique boat anchor of a motor, you could spend a couple grand on a well built SIX CYLINDER and have a kick *** ride that would eat most v8s! The 340 (or better 360 magnum) would be scary fast. And it would probably be easier to install the Hellcat HEMI for not a lot more than you would spend on obsolete poly parts. It all takes me back to the old saying "If you WORK at it, you could probably put a saddle on a COW! It would take some engineering and then you might even be able to RIDE it! It's just NOT THE RIGHT THING TO DO!
 
RustyRatRod said:
A 331,354, 392 Hemi will fit, why not a Poly? I like the idea.
Click to expand...
Or a 241. LOL

241 red ram.jpg
 
The poly guys are a niche group. I love the idea of the poly but in early B bodies. That is where it belongs. They can be made to really run for that it is, but the cost is pretty pricy.
 
Yes the swap does not make sense in the practical world. But this guy maybe wants
what he wants for no other reason to have sometime different. Poly engines look cool
and have a good rep. Someone had a 65 barracuda a few months back on Ebay for sale with
a stroked Poly w 4spd, engine bay looked OK from the pics. A local guy has a 65 barracuda with 383 said was fairly easy, had to angle the steering column over.
 
Poly had same HP as a 67 318. Without the weight or width penalty. 318s are almost free here. 727 in a narrow A is no big deal, just overkill. Just hammer the body seam flat at the bell housing. They fit fine, no cutting needed. Had one on my 340'd 65, thought it was factory trans when we bought the car until we saw the truck shifter out the hump.
 
pishta said:
Poly had same HP as a 67 318. Without the weight or width penalty. 318s are almost free here. 727 in a narrow A is no big deal, just overkill. Just hammer the body seam flat at the bell housing. They fit fine, no cutting needed. Had one on my 340'd 65, thought it was factory trans when we bought the car until we saw the truck shifter out the hump.
Click to expand...
Only the 2 barrel poly had the same rating. The factory 4 barrel version was rated at 255 hp and the dual quad version was rated at 295 hp.

The weak link in the polys performance is the log style manifolds. Swap those out and power jump 15-20 percent in most cases.

Poly heads out flow all the factory LA heads and even a lot of aftermarket ones. So it’s quite possible to make some serious power out of them
 
thesiren74 said:
Polys look amazing i say do it instead of the same old la.
Click to expand...
My thanks to everyone for their insight and comments. After reading all the great advice, I tend to agree with the majority, that it would be more work than its worth. I do like the "coolness" of the poly motor and how it can be built to the moon, but this Cuda doesn't need 500 HP. Maybe my next Project! I have a mildly built 273 and just need to find an 18 spline 904 for it. I'll try that first. Thanks again.
 
You must log in or register to reply here.
-

Back
Top