It's 18 degrees out and I have no boat, the tax man looks to be pulling stuff out of my wallet instead of putting in, and I've eaten half a box of peanut butter pattie Girl Scout cookies, so here is a hypothetical question.

Assuming you have a pair of tired 454 Mags, the 420 hp version from back in the late 80's early 90's, what would you do to get a reliable 550-600hp, on a reasonable budget?

Just interested in how different folks would approach this - N/A, small blower, crate 502's, what? And what do you think the budget would be? I realize you could write Sterling a check for a gazillion dollars and get some new motors, I'm interested in something less drastic.

Again, hypothetical but it gives us something to talk about while we're waiting for the popcorn to finish popping on the Chief thread!

KAAMA's got a pretty hot set of cams for sale that should get you close.

I would go with a set of Scat nodular steel cranks, 4.250" stroke, set of 6.385" I-beams, and SRP pistons. Balanced you can get these kits for around $1700 each. Bored .060" you would have 496CID.

You have the 990 heads, so I would have them bowl blended and matched to a set Victor Jr. takes. Intakes will run you about $250 each. Port work should be around $1000 including valve job.

Go with hyd roller cam and lifters. Around $850 per engine

So for around $3500 to $3800 per engine you could have "500" inch mills in capable of a reliable 550HP.

Chris

If you had 502's I would put a set of aluminum heads, Intake and bigger Cam but with the 454 I would go with the small blower to make the power.

Yep, what he said!

What if you had a 496 H.O. ?? Besides raylar's 7,000 dollar kit ??

Don't you mean 320 hp?

ET, as I understand it Merc made 3 big block motors back in the day - I assumed all were 454's.

1. 330 hp
2. 365 hp
3. 420 hp

Is this incorrect? I've seen a large number of boats, from Formulas to Cigs, advertised with the 420hp / TRS package.

What I did was trade in my 454's to my engine builder, then I had him build me 2 Dart Big M 540's. They should be 575-600 reliable horsepower. At a low low price of 9,000+exhaust each.

Docker- The 420 hp version had a steel forged crank, good rods, etc. It would be a shame to mess with those but trying to get 600 hp out of 454 inches means a solid lifter cam or as Tyler says a small blower.

Realistically for 600 hp in a NA engine you need 500+ cubes without going to radical. That means a stroker kit with new crank, rods etc. which you can price and have an engine shop do for you.

Looking at an older Formula w/ 420'?

Wannabe