Bone chased  has 12v  thought you might have had something   there got a little excited Damn

Time to get nitrous

Get it all the way up to 4,000 ground pounding RPM.lol

GT

Butterflies open to WOT?

And it's not popping or cutting out at wot? Just gets to s certain rpm and just stops pulling?


Sent from my iPhone using SoCal Jet Boats

Damn Chevy.... Bet that ford next to it in the picture revs a lil higher.......😜

I'm starting to think the cam timing is a million miles off.

Do you have a cam card and a degree wheel?

It will be something fundamental.

GT

Damn Chevy.... Bet that ford next to it in the picture revs a lil higher.......😜

your right bit the cam in sounds a little shity.  Haha

Exactly  what happens  runs great all the way through just stops at3900 GPS on phone says 47mph

50mph wish a stock 454 is probably bout right. In my 19ft day with a mild built 460 was only 55mph.

Post if you go and I'll see if I can make it out.

Exactly  what happens  runs great all the way through just stops at3900 GPS on phone says 47mph

You're not the only one scratching your head. I have basically the same boat, heavy as hell. Most I've seen for rpm is about 4200 at 50-52mph

Only other time I've seen this happen was because of too small of a carb but a 850 should be more than enough. Like everyone's sayin depending on the impeller that might be all she's got


Sent from my iPhone using SoCal Jet Boats

Poked around on Cranes website and found this-

'H-286-2 2400-6200
 
226  .534" I
236  .553" E
112
Hydraulic Flat tappet'

Leads me to this-
Run a Compression Check. If the Cam has a flat lobe or two, It will not perform, and 'eat' itself up.

Sounds like the Ignition system checks out, as well as fuel.

The lift of that cam, Exhaust especially, might, and I mean MIGHT be getting interference between the valve stem seal and valve spring retainer. (I had to clearance ~.100" on a .578" lift cam, to end up at .040-.050" clearence) that will kill a lobe or 8.

As Glenn mentioned earlier, Cam timing, this would also show up in a compression test.
As would a busted valve spring, bent pushrod.

The other thing thats sticking in my head...timing @ 8* btdc, and 34* btdc at ~2500. 'Typical' GM HEI has 20-22* mechanical advance. The numbers don't add up (28 to 30*, total is what I see)

A bone stock smog '78 wrecker 454, 210 hp (GM spec) pulled 4400 (with an 'A' imp.), on the primaries of a 750 holley.

That (your) 454 is still missing 1000 rpm or so.
Back to basics.

Dan'l

 

On a stock 454 that 850 carb may be too much. Just a thought