Hawk 525 vs merc 525?
 

Does anyone know the actual differences between the 2? I have found quite a bit of info on the merc motors but not much on the hawks. A few have said the hawk is just a 420 with a blower. Any truth to this?

Hawk ran higher compression and less timing than the merc. That gave it a different torque curve.

Not to hijack, but to expand...

Was quality comparable?

Did Hawk also build a 575?

yes, the two we rebuilt in the 90's were basically 420 's with bm 174's .

174s or 177s? I've read both guess I'll have to look for some numbers on the blowers

My Hawk 525 has a 250 on it. Not sure if previous owner upgraded it.

Must have been upgraded seems its a pretty common upgrade

Hawk 525sc's were Merc 420's with B&M 174 blowers.

Merc 525SC's used a lot of the same major parts as the 420's. Same block, heads, and cam. Merc ran lower compression 7.5:1 pistons, more boost and more timing. They used Weiand 177 blowers.

I have a set of Hawk 575s??? They have B&M 250s on top. I believe the previous owner upgraded the blowers.

So, were there two models, 525 and 575?

Merc 525 ran a Weiand 177. Hawk 525 ran a 174 B&M. Ocean Performance was the entire start of that with Bud and Craig.

Never heard of a Hawk 575. Do they have original decals???

Griff,

No "Hawk 575" decals present on engines. Only the Hawk World Champion Supercharged stickers on the flame arrestors. The valve covers just have the Hawk emblem on them.

Really I am speaking of what I was told from the previous owner. I was looking at old original dyno sheets from Hawk Marine at Fort Apache, reported 576 HP @ 5200 with the B&M 250s. This may have been an upgrade "one-off" built at Hawk that was arranged by the owner, I can't really speak on that one.

FWIW, I inquired on a '95 Powerplay that is supposed to have 575 Hawk engines. Below is a pic of them.

That would be the same exact setup that came with my TG. I would say that is correct as far as I can tell from the picture.

525 = 420 with a 174 B&M blower single carb
575 = 420 with a 250 B&M blower Dual carb sometimes called 600's too.

There were tons of 525 set ups built. There were a few of 502 set ups with 174 setups but they were hit or miss if they stayed together (502 setups).

bolth were built on stock Merc Motor that were Brand NEW!

FYI I used to work at Hawk and I built a ton of these motors. I was there when the splatter paint of the motors was just getting started and the 1000 NA MOUNTAIN motors were built. I was there in 1991 -1997.

Chris good talking to you yesterday, thanks for yet another history lesson! See ya soon!

How can you tell a 420 from a 502?

Roca marine said they were 502s (hawks) in that boat! And had issues but new blower fixed them. Or is it what was stated above the 502 the issue?

The 420 is 454 based. On the back of the block below the head you will see a rather larger 7.4l casting mark on a 454

Yep, I believe you're right. I'd definitely want to investigate that further to determine if the issues were taken care of. Hmmm.