I'm looking for a engine to replace one out of my 31 ford. I had a 350 that seems to have spun a rod. I'm looking at 383 rebuilt engine from blueprint engines. Since they are sold at summit and jeggs I feel sorta safe with them. My real question is; Since this is a external balenced engine, how can they sell the engine without harmonic balencer and flex plate? I thought those HAD to be balenced with the engine on a 400 (383) as oppsoed to internal (<350) balenced engine? How does this work?

P.S. Anyone heard anything about this particular engine/company? Any info greatly appreciated!  

Flex plates and harmonic balancers only need to be neutrally balanced. Only the rotating & reciprocating internal engine parts need to be adjusted for on the crankshaft itself...

External balance just refers to the weight that needs to be attached to the balancer/flexplate to balance it. Internally balanced pieces are balanced from production and don't need a set weight bolted on to balance them.  

If I read your post right, your saying that the HB and flexplate on both internal and external balenced engines are balenced to themsleves (neutral)? So whats the differance between them? Just the way they are balenced? One adds weight and one is reduced?
Thanks for your reply.  

You have idea. The only difference is that one uses a weight bolted on to it and the other has it's own mass balanced from production.  

Is that (external balence) to offset the extra mass of a larger displacement engine? Sorry for all the questions but I'm just trying to learn.    

that is basically the case for the 400 sbc rotating assembly. it was cheaper from the production standpoint to move part of the counterweight to the outside of the block. the crankshaft can be internally balanced, but that means increasing weight of the counterweights on the crank with mallory metal which is rather expensive. too costly for a production engine.
clearance inside the 400 block was so tight that a smaller rod was used to keep the longer stroke package inside the standard smallblock's dimensions. there was no room for larger counterweights on the crankshaft so that was done outside with the external weights on the balancer and flexplate.
keep asking questions, that is how you learn.  

find a stock bore 350(salvage yard), have it punched .30 over, buy a 400 crank, and attach 327 rods to the pistons.....your local machine shop can do this waaaaaaaaaaay cheaper than a crate motor......and balance the motor for you, so no worries. Alot of internet Hot Rodders have gotten used to instant gratification hp...which is all fine if your a freakin' millionair....alot of things 'the busted knuckle era can do ourselves...it's really not hard.  

I'm not adverse to doing it myself but I cant get the parts for the price of a rebuilt crate. Check out this engine;
http://www.blueprintengines.com/popular_configurations/index.html?topic=specs&pc_id=25  

ya gotta love those crate engines. i've assembled a fair number of engines for friends and myself. you can't build a comparable engine for what a crate costs. add the fact that it's assembled by a professional builder and comes with a warranty, it becomes a no-brainer.  

Not sure that I agree with all that has been written above.  You are correct to assume that all but the very high dollar 383s must have the harmonic dampener and flexplate or flywheel attached to be balanced properly.  I'm guessing that they are balancing the engine if it is balanced at all with what they consider an average weight for each.  

I'll add what you probably already know.  The 383 generally uses the 400 harmonic dampener and flex plate that are not balanced in themselves.  

I think you'll find that the Blueprint engine is internally balanced. It would not be possible to sell an externally balanced rotating assembly without a dampener or flexplate. That would require a rebalancing once you've purchased the rest of the parts. In a internally balanced rotating assembly,the flexplate and dampener are neutral and have no effect on the balancing procedure.  

Where does the vacuum hose start/end on 1997 S10 Chevy pickup truck?  Can find diagram with illustration.-  

Where does the vacuum hose start/end on 1997 S10 Chevy pickup truck?  Can't find diagram with illustration.-