Why this cam in a 420?
 

I just pulled the cams out of my supposed 420s and found these cams. Any thoughts on why someone would use them, any advantages? I'm stumped.
:poopoo:

This might help http://www.crower.com/index.php/cams...aulic-cam.html

that sure is a mild cam,maybe worried about reversion?

Maybe they want all the power band right at about 5,000 rpms or so and lots of low end. if it's in a 40 formula , It's a big boat and it needs low end grunt to go anywhere. I have stood next to one and it's a huge friggin boat

Were there any reversion issues with the 420's. It has the gil exhaust with the welded on mufflers. I'm planning on changing the cams to the crane 13-2561

I could not get it over 4,400 rpm on one engine 4,150 on the other that's why I tore into them.

what props are on it?

I cant see a cam,
but from my experience a real 420 cam are almost impossible to come by so most are substituted.

23 pitch mirage 3 blade,also tried hydromotive 23 4 blade no change

Real 420 cams are Crane 132561 and are readily available

I'm not positive, but did your boat come from Illinois? If it is the boat I am thinking of, I thought at one point it had small superchargers. Either way, that cam sucks.

Honestly, I had one of those 402 Formulas. They are friggin tanks. I had around 600HP per side, and a 25P 4 blade netted me around 5400RPM, 70mph in some chop and trimmed out. That was full roller engines, Dart aluminum heads, stellings headers, 5lbs of boost.

I think a 23P prop is too much for that boat, even if you had true 420HP engines. Get the engines in good health, and I think you're gonna end up with some 21P, or even 19P 4 blades. With 400HP merc's, those boats ran around 55mph at best. Try some 21P Merc Revolution 4 blades. My 402 liked those props the best. Planed great, good cruise, and good top end.

Hi Mild, yes that is the boat. The engines were changed before I bought it and were supposed to have had the top ends freshly rebuilt. They were in reality thrown together with left over parts, mismatched junk. 41 mph when I got it home. tore into one engine last summer (during boating season at the dock) redid heads worn seals, guides, weak springs. different style rockers ect. threw it back together to salvage the end of the season. Now I'm having the other heads done and replacing everything on both of the top ends. I did get it to 50 mph last fall. I will be happy to see 55-57 once done. Derreberry Performance is doing the heads and once I get them back together I will start playing with the props. I am thinking someone took some mags and threw in whatever they had laying around and threw them in the engines.

Right on!! Takes balls to freshin up a motor at the dock !! (;

Griff, you know better. lol. http://www.offshoreonly.com/forums/g...-vs-440-a.html
The original 420 is a Ultradyne cam but you are right the Crane cam is a close substitute and after talking to Bob I was very happy using it in a motor I built a few years ago.
As for the Crane being readily available,
Summit - Estimated Ship Date: 4/15/2014 (3+ weeks)
Amazon - Not available
Jegs - is down now but the last time I checked was weeks also.
and I wouldn't trust any of them to ship when they say they can. I waited a couple months and then canceled my order when I found one on eBay (new in its original box, almost wanted to keep it for nostalgia reasons).

The 420 was a crane cam. The 440 was a ultra Dyne.

I Already have the cams and the gold rockers. got them from carshop.com in stock and less than the others but shipping is a little more.

Not balls just a thin wallet. It was either pay someone to pull the engines or buy parts.

Cool. The carshop seems to have better prices on some stuff than summit and the others.

Do you know if your engines are original to the boat? Wonder what size intake valve they have in the heads?

Mild, they are not original located previous owner and was told he bought a 1989 357 and swapped the motors before he sold the 402 im going to measure the intake valves this weekend whenI get back to the lake

Ok just got back from the lake the intake valves are 2.19

:poopoo:Ok so I'm guessing not only did the engines not only not have the top ends freshly rebuilt, as advertised, But they are 365's NOT 420's Fi_ick me!

Nice. Always good when someone slaps engines together, with some $hit cams, those were $hit btw, mismatched rockers, etc.

You do have the forged domed pistons I hope, and not the dished 330 pistons?

The number on top of the pistons are 14097021

You couldn't turn rpm so you added MORE prop?

When I first got the boat I had the 4 blades sitting around and tried them. Issue was top rpm port engine 4450 starboard 4100. I should have the engines back together next couple weeks then I can start figuring out the props.

Did you find anything obviously wrong with the engines when you tore them down, besides the conservative cam?
I agree with thunder, that 21p is prob where you will end up, even 19p if you want to spin those new cams up to peak.


**sorry, just read your post above about mismatched parts, good luck to you. Now you will know what you have, and peace of mind.

I bought 2 of them so I agree

Hi4bus No reason to be sorry I RRRRealy am greatfull for all the assistance I get. It has been 30 years since I built motors, and back then it was small block cars not big block boats.

Sooo the next question is is the advance curve different 365 to 420. I'm hoping to fire one engine up next week. I have the advance curve for the 420.