La heads on apoly 318

[Sadie_the_66]

I have a 1966 plymouth satellite that came with a 318, according to the fender tag, but it has la heads on or even an entire la engine in it. I'm trying to mainly figure out if it is a whole la engine or if it is a poly block with la heads. Thank you.

 

[Lefty71]

I think it is possible to swap LA heads onto a Poly. But in a '66 built car, I find it hard to believe anyone would go to the trouble when a complete LA 318 would bolt right in (actually in any year after '62?? ). I say this because there are many, many parts that need changed to convert a poly to an LA, including pistons obviously, so total teardown to do the job.

LA 318 engines came out in '67, as you probably know. There is a casting date on the side of your block, that may speak volumes, if you can read it.

 

[toolmanmike]

The pistons are different as well as the valve lay out. The cam would be ground different as well. So to answer your question, La heads may bolt on but probably wouldn't work without a lot of modifications.

I have a 1966 plymouth satellite that came with a 318, according to the fender tag, but it has la heads on or even an entire la engine in it. I'm trying to mainly figure out if it is a whole la engine or if it is a poly block with la heads. Thank you.

 

[Dave6T4]

Could you get a 273 in a '66 B-body? I know you could In '67. Maybe that is what it is.

 

[Sadie_the_66]

I think it is possible to swap LA heads onto a Poly. But in a '66 built car, I find it hard to believe anyone would go to the trouble when a complete LA 318 would bolt right in (actually in any year after '62?? ). I say this because there are many, many parts that need changed to convert a poly to an LA, including pistons obviously, so total teardown to do the job.

LA 318 engines came out in '67, as you probably know. There is a casting date on the side of your block, that may speak volumes, if you can read it.

Thank you, I'll have to find the casting date.

 

[toolmanmike]

Could you get a 273 in a '66 B-body? I know you could In '67. Maybe that is what it is.

2 barrel 273's were available in 65. I would love a 65 Dodge with a 273.

 

[Dave6T4]

Yes, 2 barrel 273 were available in 64. I would love a 64 Dodge with a 273.

273 was only available in A-body in 1964.

 

[toolmanmike]

273 was only available in A-body in 1964.

Thanks, I thought I have seen one or two in a 64 but it probably was a 65.

 

[Diodedog]

The pistons are different as well as the valve lay out. The cam would be ground different as well. So to answer your question, La heads may bolt on but probably wouldn't work without a lot of modifications.

The poly pistons should work fine and give a similar comp ratio with 318 LA heads on it but will require an LA cam as well.

 

[toolmanmike]

The poly pistons should work fine and give a similar comp ratio with 318 LA heads on it but will require an LA cam as well.

as long as you don't need valve reliefs. Poly pistons are like Hemi's and have reliefs opposing each other on the outer edges. LA's relief's are inline. (wedge head design)

 

[Diodedog]

as long as you don't need valve reliefs. Poly pistons are like Hemi's and have reliefs opposing each other on the outer edges. LA's relief's are inline. (wedge head design)

View attachment 1443243

The cam would have to be fairly small duration wise and the poly CH being approx .030" higher will make up for the lost CCs in the valve notch.