Did you get a new boat?.... Awesome! But please let us know what happened with the original problem...... Any competent machinist would have certainly checked valve timing and piston to valve clearance...... Do it yourself if you have to and get a solid lifter and some clay. Get some help from a fellow gearhead and don't let that machinist bull**** you any longer. I would not start that engine until you check those items as you are dealing with unknowns..... What cam? What pistons? Etc......don't leave anything to chance, check it ALL. Then you will know everything is right............ TBF

Honestly I got sick and tired of dealing with the machine shop. We don't have a lot of options here for machine shops. They told me there was nothing wrong with the engine and to put it back in. They also didn't put a degree wheel on the cam but stated that they had checked it and that it was fine. I did a little soul searching earlier this week and I know If I put that engine on the dyno and it popped again I was going to come un-glued. I also refuse to waste another 12 hours stuffing that engine back in without knowing it's right so I told the owner of the machine shop I wanted my money back. We struck up a deal and he bought the engine. I thought that was somewhat honorable but it of course still cost me money but probably not as much as trying to sell that engine afterwards. Our boating season isn't that long so I sold the Pachanga 22 with the stock 7.4L to a friend of a friend (it ran perfectly on that old fuel just for the record) and bought a fresh water Donzi 28zx with Procharged 350 Mags and 139 original fresh water hours. I'm pretty familiar with this set up as a had a Scarab 29 set up the same way and it worked very well for me, fuel efficient and fast. If something breaks on the 350 Mags I can just call Michigan Motorz and have them ship me a new one for about 3K with a 3 day delivery time. Just seemed like the best solution to a very very very frustrating start to my boating season. I do really appreciate all of the advice from everyone and I apologize for pulling the rip cord before the answer was found. I don't think that I'll ever attempt to build another bbc. This has been exhausting.....

I am glad to see you got your problem resolved. Good Luck!

I know the motor deal is over and done with/gone but I will share a recent story of my own and the importance of checking cam timing with a actual degree wheel. A customer of mine came to me with a problem child oldsmobile he had been dealing with, 66 olds cutlass with built 425 olds motor. He paid good money for a SUPPOSED engine builder to build it, motor was a turd and never ran worth a crap. for a 10.5-1 motor the comression was awful low ( I expected to see 180-200 cranking and it was closer to 140-145) Had it in and out several times and even back to the guy to go back thru it. The third time he had it out the guy took it back apart and said it needed new valves, cam and lifters, this was 50 miles AFTER he had just been thru it. The owner decided he was done with original engine builder and would just straighten it out himself. I build transmissions, transfer cases, axles as a business and build a ocassional motor so I agreed to help him out and over see what he was doing. The cam was supposed to go in at 106 degrees, when I degreed it we saw 115-116 degrees (9-10 degrees retarded), no matter how we lined up the marks using the advance or retard we could only get it to about 112, the timing chain was of unknown origin and owner was spent out on money refusing to pay 200$ for a Cloyes hex adjust or equivilant. Even if he would spring for a special timing set no one had one on the shelf for a olds so to expedite things I got creative. I put his upper cam gear in the mill in a rotary table, lined it up until a transfer punch went thru his original cam pin hole perfect, I then turned his cam gear 180 degrees plus 5 cam degrees, repunched another 5/16 hole thru the gear, counted 24 of the 48 teeth, remarked his cam gear and re-installed it. We were able to get the cam timing to about 105 degrees, slightly advanced so that when the chain stretched under a load the timing should be about perfect, took longer to drive from his shop to mine than it did to modify the gear. To make a long story short the thing ripped when we were done with it, had 195 psi of cyl pressure. He called up the original builder and asked him WTF he did when he degreed the cam, the answer was he "degreed" it by lining up the timing marks!!!! POS supposed engine builder, ANYTHING can skew cam timing, crank was reground off slightly, chain set is off, cam is cut wrong, too many people make assumptions as to cam timing, those "marks" are just a starting point, not sure what happened in the case of the engine in this thread but if he had proceeded further actually degreeing the cam would have been the first thing I would have done, Smitty

Smart move!!! I did not realize you were up, or should I say way out east in Halifax! I used to fly for Comair before Delta decided to shut us down and I have been into Halifax many times...... I always looked forward to taking the ferry across and having a few cold ones at the great pubs.... I have seen some very nasty weather up there and I am sure your boating season is short. Good luck with the Donzi and I hope to get my Donzi going soon as well..... Smart move dumping the engine! TBF

Its probably corrosion behind the valve guides caused by reversion, this makes the valves stick when they get hot.
Happened to my engine.

Nice boat what was the problem I'm interested? sorry missed the above.

ok, you can ck piston to valve clearance with all together, pull the plugs, put air in a cylinder remove both valve springs, if you have seal they will keep the valve from falling down all the way, remove the air, with piston on TDC set the lash to 0, now let the valve sit on the piston top, roll the engine over with a rachet..NO STARTER....hold down on the rockers and watch the clearance between the rocker and valve...at the closest point this is your true piston to valve clearance...I always use this as clay can lie....if the valve hits the rocker you have a problem...or if less than your min clearance should be including the head gasket...if that lower timing gear is on wrong as some stated will take away the clearance...but this way you will know quick..