Mercruiser 420's single plane or dual plane??
#61
Registered

Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
I'd definitly double check the merlin part #'s, if possible. The #030620 was a 320CC intake runner, iron head. The 030630, was a 345cc intake runner iron head.
Was there a "b" or "C" after the "1-043" stamping? The B would be 320cc, C would be 345.
Was there a "b" or "C" after the "1-043" stamping? The B would be 320cc, C would be 345.
#65
Registered

Joined: Nov 2005
Posts: 1,028
Likes: 2
From: Grand Rapids MI
#66
Registered

Joined: Nov 2005
Posts: 1,028
Likes: 2
From: Grand Rapids MI
This is the reason i had mine dynoed again. Just to see if any more power was left on the table. I found out i need to port my heads and do a cam change and that is what would be expected out of mine.
#67
Thread Starter
Gold Member

Joined: Oct 2005
Posts: 11,691
Likes: 217
From: Olmsted Falls,Ohio Marblehead,Oh
Ok, so I put same engines in my new ride (35 Mistress) that is a ton heavier, only lost 2 mph and gained 3-400 rpm with same props...I saw 63mpoh@4900 and thats aboput where these cams are done... I am thinking with custom roller cams I can grab a few more hp out of em...



