What would be your recommendation?

if it has the origional pistons and heads i would go around 34 total timing,on the jets id fatten it up a little but the only way to properly jet it is with an air/fuel ratio gage imo.on that engine with no innercooler i would shoot for 11.0 afr just to keep it safe.

I was just taking to him about adding an o2 for a/f to get it tuned right. Can that be added to CMI headers?

+1
Lots of good info guys THANKS!
Bill

Also guys recommendations on O2 sensor and gauge will be helpful!

Bill,
You didn't have a hillbilly with a Dodge truck do any of the work did you? There've been reports of the same guy doing shoddy work around the Fort Meyers area, usually preying on seniors, but I guess he got greedy! I think he's part of those Irish scammers that travel the country. Don't let him seal cote your driveway, it'll wash off with the first rain! Lol

I'm sure he will chime in and I Have to give a big thanks for all his help and everyone involved!!! We did this in a couple of days with the motors still in the boat! This was supposed to be a shout out for a little help with propping this old gal looking for anyone with this similar setup sorry if I went into detail. I'm working on the fine tuning of the motors at this point . This has turned into a little technical motor help witch is fine at this point and I give big thanks to everyone's input. I put a lot of thought and time into this so far and I really think we have the tuning figured out just looking for prop ideas 28's 30's? or....

BTW I was just going to tune up the carbs and freshen up 1 set of heads and the plot thickened LOL... I'm very happy with the setup I went with and cant wait to have her dialed in!! Only missed 1 FMO run this month but not really took Dave's C.C.

i have cmi,s,i put the o2 sensor in the tail pipe and i remove it after tuning and put a threaded plug in the hole.i like the fast dual bank setup.

Thanks Mike!

The 525SC timing spec is 35*. Yes it is.
Here's the problem many run into setting timing on this motor - the factory advance curve does not reach total until around 4200rpm. I found this rpm total out tuning a set of 525SC's that had intercoolers installed and different pulleys. Motor had blown headgaskets. Why ? Some one set the timing at 35 *F at 3500 rpm. I kept reving motor until advanced stop, as I do with all motors cause I don't believe anyone, lol.

Rev it until the advance stops advancing and set you total there. Again, Factory calls for 35*.

26* will make it a turd unless you changed pistons or etc for more compression. Even if you did, it would probably like a little more advance.