You just have so much working against you on the 534. Excessive weight (about 1100 lbs.), very heavy reciprocating assemble (forget anything north of 4000 r.p.m.'s), and a really screwed cylinder head with small ports and valves, not to mention the combustion chamber being formed by the block deck being machined on an angle and a 'plank' head. The intake manifold is really stange on a lot of them too, partially cast in the heads. Even if you could do something with a 534, what are you going to put it in, an F-800? Really tall for any pickup truck. I know a guy that built a 478 GMC V-6 and put it in a '69 GMC pickup. It actually worked, the smaller V-6's were used in pickups, so the installation wasn't a problem, and the 478 had some pretty good heads and manifolds. He used a huge Holley 2 bbl. carb. and had a cam custom ground. A really neat truck when he was finished, but a big block would have done better at half the price!