Small block strength

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OleNatesOlds

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I'm considering a small block for my Dart (if I can never find a 400) and want to know opinions AND facts about small BLOCK strengths and weaknesses. 318 poly, 273, 318, 340, 360, 360 magnum, etc. Specifically why you feel one size and era is the best over others (wall thickness, main saddles, hardness, parts availability, etc.). Let's exclude rare stuff like 340 t/a blocks and such since this thread is inspired by a budget build. Thanks
 
400 small block or 400 big block?

A 400 "B" big block engine can be found in things like a Cordoba or any other like B body and earlier 73-ish Road Runners and like B body cars. Also, C body cars. (Bigger than B body cars) like an Imprial. SP!

The thing with small blocks is mostly mains. After that, major failure area I seen once was a guy boosted his sb and split it in half right down the cam journals.

Since your doing a budget build, what ever budget means, how much power are you looking for?
 
According to the mopar small block book I have , if you cant afford the 340 siamese block like the TA, then your next best thing is an early(71-73) 360 block, because they were cast thicker. according to the book you can bore the early blocks out to 100 over without having to worry about them cracking the cylinders if you run it a little too hard. and the 360 can be found in anything from trucks to a,b,and c bodies.
 
i think 360's are the way to go, honestly, when i get my mopar it will have either a 360 or 440. (440 for a pro street) your best bet for a budget build would be a 360 JMHO
 
OleNatesOlds said:
I'm considering a small block for my Dart (if I can never find a 400) and want to know opinions AND facts about small BLOCK strengths and weaknesses. 318 poly, 273, 318, 340, 360, 360 magnum, etc. Specifically why you feel one size and era is the best over others (wall thickness, main saddles, hardness, parts availability, etc.). Let's exclude rare stuff like 340 t/a blocks and such since this thread is inspired by a budget build. Thanks
Click to expand...

Alot of those issues don't matter much unless you are pushing the limits on hp. If I had to find a small block to build-up (like my 408) I would go with the 360 or 360 magnum for the stroke and displacement. If you're going to do a stroker then 340 is fine but harder to find and more expensive obviously. I personally think the big block is a better design with the distributor in front, external oil pump, better head bolting, etc although I don't like the rear seal and windage tray design. If you can believe what you read the 400 is a great engine and has great potential in a stroked configuration. I bought a 400 block a few months ago for $100 and I could have bought 2 more. They are out there.
 
Small blocks especially 340's hold up very well to abuse...get a 340 and "stroke it" of coarse...:-D:-D
 
Nobody has mentioned 360 Magnums; for what reason, I don't know, but they have the advantage of an OEM roller cam. The available heads for them include the IronRam (?) cast iron from Hughes, and of course, the Edelbrock aluminum in a variety of flavors.

Unless you are going to extremes in power production, I think you might be satisfied with a 360 Magnum. My engine is a 360 Magnum (stock bore and stroke) and, with nearly stock heads and a mild, 214/216 @ .050" lift, has been chassis dynoed at 445 rear wheel HP and 47o rear wheel torque, utilizing 10 pounds of boost from a Vortec supercharger and a blow-thru 750 Holley, on aviation gas.

No problems, yet, but tomorrow could have me singing a different tune... These cast pistons (stock) and composition head gaskets may not live indefinitely, with boost.:angry7:

That's all I know, for now...

Good luck!!!
 
It's mentioned Bill.

Ahh, guys, he said budget. A stroker done on a budget?
 
There is virtually no difference in the blocks as delievered from the factory. The early 360s were supposed to be good, but core shift due to poor casting ruins those most of the time. The thickest block I've tested is being done now... It's an '89 roller cam LA. I find blocks after '72 tend to have better casting quality and less core shift. But it only takes one hole to make the block need a sleeve for any stroker project. If you stay factory displacement, anything up to .040 is fine. I'd sonic test anything going over that. It's up to your budget and your wallet. Fill in the blanks for budget and goals, and we can get more specific. The best street engine is the longest stroke in any block.
 
>>>"It's mentioned Bill."

And he was RIGHT! I just scanned too quickly, and missed it.

Thanks for the correction.

Is an R-3 a "budget" item?
 
Believe me if I find an early 400 that's not bored out crazy, I will grab that puppy over a small block and then it's a different topic. Yet, it looks like 360s are going to be the most abundant candidates around here. So if that's the case, I'm looking to make 400 RRRWHP (Reliable, rock-solid, rear wheel HP!) for years to come. Normally aspirated, street driven mostly, pump gas, enough vacuum for brakes, carb or EFI?. I wanted to leave induction vague because I don't know if the Magnum system can support that or if it requires major mods. I do like the factory roller cam in it. If they are generally beefier, can pre-mag blocks be retrofitted with magnum components?
 
OleNatesOlds said:
Believe me if I find an early 400 that's not bored out crazy, I will grab that puppy over a small block and then it's a different topic. Yet, it looks like 360s are going to be the most abundant candidates around here. So if that's the case, I'm looking to make 400 RRRWHP (Reliable, rock-solid, rear wheel HP!) for years to come. Normally aspirated, street driven mostly, pump gas, enough vacuum for brakes, carb or EFI?. I wanted to leave induction vague because I don't know if the Magnum system can support that or if it requires major mods. I do like the factory roller cam in it. If they are generally beefier, can pre-mag blocks be retrofitted with magnum components?
Click to expand...

If you're convinced that you don't want a supercharger, I think you might be better off to look for a pre-Magnum 360 with OEM roller tappets because, I think there is a lot more out there in terms of cylinder head choices (L-A-compatible) for a Pre-Magnum setup. Magnum heads may be an improvement over OEM L-A heads, but they're just not that good,compared to even an "econo" L-A, W-2, in my opinion.

The late model, roller-equipped L-A block would seem to give you the best of both worlds. I don't believe you'll have much trouble finding a roller non-Magnum 360; they were in a lot of vehicles in the late '80s.

Good luck!
 
Bill Dedman said:
>>>"It's mentioned Bill."

And he was RIGHT! I just scanned too quickly, and missed it.

Thanks for the correction.

Is an R-3 a "budget" item?
Click to expand...

No problem Bill. Good question to the poster.

moper said:
The best street engine is the longest stroke in any block.
Click to expand...

Amen brother! That's my opinion as well.
 
curts73 said:
According to the mopar small block book I have , if you cant afford the 340 siamese block like the TA, then your next best thing is an early(71-73) 360 block, because they were cast thicker. according to the book you can bore the early blocks out to 100 over without having to worry about them cracking the cylinders if you run it a little too hard. and the 360 can be found in anything from trucks to a,b,and c bodies.
Click to expand...

they should have said any 360 block. i sonic tested a few and you can safely go to a 4.10-4.12" bore no problem. jmo.
 
moper said:
There is virtually no difference in the blocks as delievered from the factory. The early 360s were supposed to be good, but core shift due to poor casting ruins those most of the time. The thickest block I've tested is being done now... It's an '89 roller cam LA. I find blocks after '72 tend to have better casting quality and less core shift. But it only takes one hole to make the block need a sleeve for any stroker project. If you stay factory displacement, anything up to .040 is fine. I'd sonic test anything going over that. It's up to your budget and your wallet. Fill in the blanks for budget and goals, and we can get more specific. The best street engine is the longest stroke in any block.
Click to expand...

I have a 93 LA 360 roller cam block. I heard too that the later years were good blocks. Not sure as I have never tested one.
 
>>>"I have a 93 LA 360 roller cam block."

I was unaware that any of the '93 motors were L-A's.

So, they were making L-A, roller-cam motors along with the 318 Magnums in 1993?

I learn something every day!!!!

What was the last year for 360/roller-cam, L-A motors?

What kind of heads did those L-A 360 roller motors have?

Thanks for any information!!!
 
Thats the last year Bill. The change came that year. It'll be writin down on paper saying one thing, but, the left overs get used up for production.

Just like they say the 360 came out in one year, but there are casting dates on the block the year before. Yep, there rollers too!!1

Woo-Hoo!

360Z28 said:
they should have said any 360 block. i sonic tested a few and you can safely go to a 4.10-4.12" bore no problem. jmo.
Click to expand...
Reallllllly! You can safely bore a 360 to .100 over? WOW!:read2:
 
Bill Dedman said:
>>>"I have a 93 LA 360 roller cam block."

I was unaware that any of the '93 motors were L-A's.

So, they were making L-A, roller-cam motors along with the 318 Magnums in 1993?

I learn something every day!!!!

What was the last year for 360/roller-cam, L-A motors?

What kind of heads did those L-A 360 roller motors have?

Thanks for any information!!!
Click to expand...

I think mine is a warranty block. The date is cast as 93. The last year it was in a vehicle was 92. Not sure what heads they had on them as mine was a short block assembly that I put Eddy heads on it.
 
The Magnum V8s started in the 92s. My '91 1-ton had a roller cam 360 LA EFI in it.
I've never seen any factory block that I would go .100 over on and feel good about it. The pin axis dimensions on many blocks get as thin as .090" at standard bore size... I even found one 340 that only had .080 of meat in that direction because of core shifting. I had to sleeve it to run it at .030 over.
 
The first post is kinda vague, what is the poster looking for? Something to hold at WOT for ever? Heavy car?

And yes, the latest 360 blocks seem to be the best. 318 blocks seem to be early is the best.
 
The best bang for the buck is a 360, any year. Make sure the core is std. bore. Just have the bores sonic tested so you can go .030 over from std. Install a mild cam and springs to match and use the stock heads with a good rebuild and a gasket match both intake and exhaust. Any good dual plane 4 barrel intake is next with a 700 - 750 cfm carb. Give it all a good rebuild with quality parts and you will have an engine that will last forever and will give you lots of power as long as you don't buzz it past 6000 rpm. I would balance the bottom end too, it's well worth it.
If you plan on adding power adders such as nitrous etc. in the future, save up and get a good stroker kit and some good heads, forged pistons, and maybe an aftermarket block. Or better yet, go big block and do the same.
It depends on what your BUDGET is, and what you have planned for the future.
My 2 cents.
Tom.
 
rumblefish360 said:
Thats the last year Bill. The change came that year. It'll be writin down on paper saying one thing, but, the left overs get used up for production.

Just like they say the 360 came out in one year, but there are casting dates on the block the year before. Yep, there rollers too!!1

Woo-Hoo!


Reallllllly! You can safely bore a 360 to .100 over? WOW!:read2:
Click to expand...
yup. i said it before that despite part #'s casting #'s etc.. a LA360 is an underbore 340 with the only major change being in the main saddle area.
that leaves less material there, but still plenty strong. and if you add 4-bolt mains.. damn near bullett proof.
 
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