So just how good are these SBM engines

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Retroboy

Retroboy

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Howdy.
I'm new to Mopar had Fords all my life. Just finished my first engine - 360 + .040 KB190 pistons, Racer Brown ST 21 solid cam, Std "J" heads but with 1.96 & 1.60 valves,decent springs etc. Also has an old Vertex magneto and a toilet style mechanical injector. Will be running methanol in a slingshot dragster with a 904 TF 4800 stall converter, 4.30 gears and a 31" slick. A very basic budget deal. I was impressed by the Standard rods and just up graded the bolts. The block looks beefier than SBC or Ford windsor but had a fair bit of crap casting flash. Liked the 273 adjustable shaft rockers I picked up at a swap meet. Don't like the exhaust ports and couldn't believe the original pistons were dished tops and .125" down the bore! Anyhow just have to sort a set of headers now - anyone have a set or some zoomies that they would part with? Chrysler stuff is scarce here in Australia - most shops don't want to talk to you about anything other than SBC or Ford. Read a few books looked at the web - including some here, and applied a life times experience and I hope it works out OK. Bought some stuff from Dave Hughes very happy and even with freight cheaper than here in Aussie. About to by a couple of bits tonight from Alki Digger then ready to fire this thing up for the first time in a week or so.
What is my combo good for? Who has some first hand experienced Mopar input.
 
Just how good are they? Well, like any other engine out there, they have there pro's and con's. 1 con is oiling. For serious performance useage, you'll need to drill the passages in the block larger. There's no real need for hi volume oil pumps.

A semi con is the cylinder head. While it has an advantage with 18* valves as stock and a easy upgradeable rocker system on a central bar, the cam at 59*'s puts the pushrods at a odd angle to the rockers. You will loose a little lift. Serious efforts in power will look to the race blocks 48* tapper angle. This becomes expensive.

The valve train of the LA engine will not need a girdle but the Magnums will since it is more Chevy like. Which also makes it cheaper.

The rest of the engine is excellent for what ever your looking to do for most of what could be done or sought.

The blocks are a high nickel content and can swallow up a 4.25 stroke. After market (MP) blocks can be bored out, up to 4.22. In theory, you could build a 472 cube small block.

Heads to feed it can get pricey though at this stage, who cares?!?!
That's my take!
 
Tell ya. There's some impressive numbers coming out of some turbo / twin turbo small blocks
 
I know of a pump gas small block that makes a little over 2hp per cubic inch. All I'm willing to share. And there is more to be found, probably another 100hp
 
The others pretty much summed them up but something I wonder is did you just replace the rod bolts or did you replace them and then have the rods re-sized? Every piece of literature I've read and every machinist I've talked to says you need to re-size the rods when you change the bolts
 
Yes Mate resized (but I reckon it's a waste of money and time). So who's going to stab in the dark about what sort of power will my engine make?
Cheers
 
You can tear them up like anything else.
 
Hp guess, around 400hp. The smallblock mopar is a very reliable engine. From what i've seen the 360's are a little harder on the main bearings than the 318/340 2.5 inch mains.

As said by rumblefish oiling mods are very important in the sbm. Them stock rods will live along time, mine are 1970 340 rods that have had the beams polished and shot peened. Been used as race engine since 1989 at around 450hp. Keep us posted on your results!
 
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