1973 400

I just bought a '73 400 engine for a future build, and I have a few questions.  It was disassembled, but all parts were there and looked decent. The block is standard bore but has some light surface rust on the bores, the crank was a cast crank, and I didn't measure them at the time but the journals looked great. The heads are 6X and looked good enough to bolt on and run.

I paid $125 for this engine, did I get hosed or is it a good deal? Are the 6X heads worth keeping and using, or is upgrading to aftermarket heads a wise move? If I do a 400 based small journal 455, should I go find a stock 455 crank, or is an aftermarket crank a better idea?

Thanks in advance for advice

Mike  

If every thing is in good rebuildable shape then you got a great deal.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

Oh and the 6X heads are decent heads low compression but flow decent.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

you can not use a stock 455 crank on a 400 the journals are to big.they make an aftermarket 455 crank that fits the 400.  

I'm talking about the builds where they turn down the 455 crank to 400 journals, a friend of mine had it done like 10 years ago. It ran great and I wanted to do the same thing but I was wondering if the Pontiac aftermarket has reached a point where the aftermarket cranks are a better choice overall.  

Be careful with some of the aftermarket cranks they are cheap chinese made junk.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

check out ohiocrank.com. i got my crank from there. $295 for nodular iron stroker crank that will fit into the 3" 400 mains. 4.21" stoke is 455 stroke. you can also get a 4.25" stroke crank from there.  

You got a great deal. 6X heads are one of the best choices for porting as they have one of the largest short radiuses. They can easily be ported to 255cfm which meets 500hp needs and I have ported many to 270cfm, while keep the runner volume low to main velocity and low lift flow.

The Chinese cranks are very bad. The North American cranks by Eagle, Scat, Ohio, are very good. Eagle cranks are cast steel, not forged having issues over 600hp and are known as spaghetti bendy by shops like Butler and All Pontiac.

The cost to adapt a 455 crank is high as the thrust areas must be welded and machined to meet the smaller width of the 400 thrust bearing (not to be confused with the diameter). To do that the crank has to be heated red hot for welding, which often distorts the crank and ruins it. Other issues can occur from poor welding as this extra thrust material can peal off in running conditions.

The new cranks are in expensive, and the best solution is to order a complete Eagle or Scat kit. Buying pistons, rods, rings and bearings on their own is more costly then buying a complete kit. It's like getting a crank for free.

Good luck...  

I agree with Ryan- some of the cast stroker cranks (w/ the exception of the new castings out from Ohio Crank, Eagle, and PPR) have problems- better to spend the extra $350 for the forged stroker unit and make that bottom end bulletproof. Or get a 455 and go factory stroker with aftermarket pistons and rods.

BTW, any new crank, cast or forged, is made in China- what separtes them is the in-house QC. Eagle's cranks and rods are for the most part good- their early batch of cranks had thrust bearing surface issues and some failures were also reported. PPR's cranks and rods are also good- I had a conversation with Ace about his importer's parts and knowing Ace (took samples, built motors and tested them for about a year) you can be assured PPR's rods and cranks are soild.

Geno