Merc 420/454 article from August 1986 Powerboat

[Pismo]

Since there has been some interest lately in the 400/420/440 Mercs, here is some info I found. I am reading the August 1986 issue of Powerboat where they cover the introduction of the Merc 420 and 575. The Merc 420 was released in late July 1986. It replaced the 400 and 440. Dyno test produced 436hp. The new 420 has a 850cfm Holley, Weiand intake, hydraulic lifter Crane cam, in house designed iron exhaust manifolds and elbows with Stainless tips. Can be ordered with a TRS, #2 or #3 Speedmaster. $21,290 with TRS, $24,695 with a SS2, and $26,575 with a SS3. In a 25’ Seebold Eagle they hit 65.6mph with a single 420 at 5000rpm. The 575 is a Bow Tie tall deck siamese block 4.44” bore x 4.375” stroke yielding 540ci. Carillo rods and 8.75:1 CR. 1050cfm Holley and Weiand Team G aluminum intake, Stellings stainless headers. SSM#3 or #4 available. $54,420 with a SSM#3! In 1986…big $$s. Cool pix but I have no scanner. This issue also covers Chip Hanauers 5th Gold cup win and that Popeyes 35’ Cougar cat that had 8 outboard powerheads thru 2 Merc drives as the power. 140mph.

[gcarter]

Hmmmm.. So the exhaust tips are stainless and pre-packaged with the unit, or do the elbows have stainless exhaust ports??
Ya know the microfiche shows Gil manifolds and SST risers and tailpipes.....
Who do you believe.....

[Pismo]

The manifolds sure look like the gils, the elbows don't. They are triangular with the tips coming directly off the back facing straight aft. The article goes on and on about the research done to perfect these new Mercruiser in house iron manifolds and elbows and how this is where much of the power gain from the 370 to the 420 comes from. I think this may have been the time when Merc was first developing their relationship with Gil and Gil was the subcontractor for the manufacture but Merc was claiming all the work was there own. They also state that this new exhaust eliminates the need for costly custom tips needed with the 440. I wish I had a scanner........

[gold-n-rod]

I wish I had a scanner........

Your local Kinkos should be able to help you out.

[Pismo]

Ya know the microfiche shows Gil manifolds and SST risers and tailpipes.....
Who do you believe.....

I am also sure they may have upgraded the elbows to something other than the cast nodular iron in the pix.

[Squiggy111]

My 1984, 22', Classic, has the exhaust in the pics on it .....however when I bought it the previous owner gave me the Gill manifolds with the stainless tubes, I've never put them on the boat????.....Do you think the Gill setup would be better as far as performance??

[gcarter]

I imagine whether they helped or not, they would add an awful lot of bling!!!:eek!:
Besides, you would lose some weight.

[BUIZILLA]

I'm going to go out on a limb here and say those GIL pieces are worth at least 20, maybe 30 hp.... a 3 -4 hp per cylinder increase, is not out of the question..

[Pismo]

Are your Gil pieces aluminium? I would think so.