Outside Engine Dimensions

mgm1986

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I have a bit of a useless question. If you were to put a naked 318 and a 340 next to each other, would you be able to tell the difference without looking at the stamping? Just the block, completely stripped down. I know internally the difference is in the bore size. Stroke is the same.

Like I said, probably useless knowledge but curious nonetheless!
 
To the average layman no, the blocks, heads, pan, valve covers, timing cover, water pump are all the same. This is true for the 273, 318 & 340, the 260 has some differences but pretty much the same.

I only say to the average layman because I can not think of any differences and I been around but far from an expert on this.


Alan
 
All the small block engines are based on the same block and head design, the only major differences to be found are internal. So no, from the outside with a cursory glance you wont see a difference in any of the engines except the 360 with has an externally balanced crank.
 
I think there is a small difference on the heads/intake dimensions.

IIRC, you can use a 340/360 intake on a 318 if you have 340/360 heads mounted on the 318.
 
I think there is a small difference on the heads/intake dimensions.

IIRC, you can use a 340/360 intake on a 318 if you have 340/360 heads mounted on the 318.

It think that difference is in the ports with no notable difference on the outside.

The early 273 had different bolt angles on the intake but otherwise looked the same.

I plan on a 318 for my Barracuda but still plan on putting the Commando 273 dress up on it.

A 340 in place of a 318 would go unnoticed visually.


Alan
 
Yes, this is really what I was thinking. I know the bolt-on pieces are different from the factory but the blocks appear identical.

Actually all the bolt on pieces are the same.

Same timing cover, same water pumps, same valve covers.

The 340 intakes are taller (dual plane?)

The only differences in water pumps are up to 69 they were cast iron with the hose on the driver side, 70 and later aluminum and on the passenger side.

There were 3 different timing covers.
1. Passenger side timing tab that bolted on.
2. Passenger side timing that was part of the cover
3. Driver side that was part of the cover
(there are some difference in early vs later on the first one)

Valve covers is about the type and placement of the breather and oil cap along with brackets for the hoses and plug wires and the shield on 4-bbl covers. Even the Commando 273 covers were the same just painted wrinkle black with aluminum trim added.


Alan
 
I look at a small block and I see a small block. You could line every one up in front of me and they'd all look alike with that distributer hole that butts up against the firewall. But I'm from the points every 1500 miles era. :D
 
I look at a small block and I see a small block. You could line every one up in front of me and they'd all look alike with that distributer hole that butts up against the firewall. But I'm from the points every 1500 miles era. :D

Until recently, I didn't realize the big block had the distributor in the front! And at Carlisle, someone mentioned you can tell the difference between a 383 and a 440 by the width of the intake manifold.
 
Actually all the bolt on pieces are the same.

Same timing cover, same water pumps, same valve covers.

The 340 intakes are taller (dual plane?)

The only differences in water pumps are up to 69 they were cast iron with the hose on the driver side, 70 and later aluminum and on the passenger side.

There were 3 different timing covers.
1. Passenger side timing tab that bolted on.
2. Passenger side timing that was part of the cover
3. Driver side that was part of the cover
(there are some difference in early vs later on the first one)

Valve covers is about the type and placement of the breather and oil cap along with brackets for the hoses and plug wires and the shield on 4-bbl covers. Even the Commando 273 covers were the same just painted wrinkle black with aluminum trim added.


Alan

That is a lot of good info, Alan! Thank you!
 
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