What heads are you running on these? Where did you set your compression ratio ? And realistically if you dont go to port injection you will constantly be chasing to get the correct tune.

Makes you wonder how balanced the AFRS are thruout each cylinder. Recently a well know engine builder said to Dan Baloun " I tune to 36 degrees of timing and mid 12s on most blower motors" , Ive NEVER came close to that witha "typical" boosted bbc, not that I HAVEN'T tried more timing and or leaner fuel ratios. I built and dynoed a "typical" 502 whipple recently, top mount 3.3, mefi batch fire, 8.8-1 compression, aluminum heads. Had 1 to 2 degrees KR on dyno at 11.7/11.8 (tailpipe) with 32.5, 33 degrees of total on top, 28/29 in mid, around 800 hp. Added fuel to about 11.5 average tailpipe, took a little more out of the mid, kr was gone, took timing down to 32 max, a "safe" tune where I wont be rebuilding motor for free in 4 hours. I rescaled the tune so I could raise fuel pressure to allow customer ability to somewhat tune it in boat with fuel pressure. Now, with my tailpipe average at 11.5 ish, my hottest cylinders were in the 12.2/12.3 ish area in certain points, thats with the mefi set to double fire also. Richest cylinder was 10.8 or so, its a BBC, without individual cylinder tuning a 1.5 afr deltas not terrible. I took 10% out of tune, bumped base fuel pressure to 50 from 42, math told me would get me close. Made a pull, afrs went to 12.2/12.4 tailpipe average, had SEVEN degrees of KR with 28 degrees around 4600 and 32 degrees at 5200, aborted pull about 5300 , fixed fuel tables back to that mid 11 area. So, it comes down to (IN MY OPINION) to run more timing, youd either have to "fire hose the fuel to it" as Crockett once said to me or to run leaner, pull more timing . Now, IF you could get those lean cylinders down that .7 points, tailpipe average could be leaned out a little, Smitty

Mercury runs 16 injectors, 2 per cylinder. That probably helps a ton with fuel distribution in the cylinder. Also they run a deflector panel under the whipple so as to spread the volume of air equally through the inner cooler.

He can correct me if I’m wrong however I recall Dart 345 cast massaged a little - 9:1 + -

ya 9:1 is way to much compression. He should drop it to 8:1 and run 10-12 lbs boost.

it’s very well possible he is. Kinda difficult to keep up with Dan the never ending Man. I give him a lot a credit though. 👍

What would the difference be from cast iron to aluminum? I always thought close to a point in CR. I’ve always run NA cast 9.5 and aluminum 10.5 static. Didn’t these engines dyno with 7-8 pds of boost?

Any pictures of this deflector plate , sounds interesting .

As you can see in those sheets , I`m at 8.3:1 running 10 psi.
12psi? no way , unless race gas.

I`m going down to 8psi, at 8psi I`ve never melted any pistons or had any catastrophic damage .
10 psi your tune better be perfect or boostane each fill up.

All this damage was done at 4psi, 4000 rpm 12.5afrs and 31.5* wot is safer than peak TQ.cylinder pressure .. so from now on it`s WOT everywhere I go

Im done chasing 100mph. I got to 95mph .
From now on Id rather have 3 summers at 80mph then one summer at 95mph.
These old heavy boats are killer on engines, so much load .