Longrange4u

ECeptor.... Great Post... that is the info I am looking for!! Thanks!

Anyone else have an opinion?

ECeptor

Another reference book I've read cover to cover several times and recommend is "Horsepower Handbook." It is a compilation of articles from HotRod magazine. I found my copy at the local bookstore (Borders).

Airpacker

I actually put 250 hard hrs on a 7.4 cast crank/cast pistons after adding a new cam, intake, exhaust, holley 800, a bigger oil cooler, roller rockers and some head work. The peanut port heads will be ok up to around 400 hp. I ran it consistently at 5200rpm for 3 seasons of poker running( ie to the dash stop)
You can make a nice 468cid, add a steel crank, 7/16 rods and forged pistons, decent set of heads, intake, crane 741 cam, exhaust, carb etc and make 500hp all day long for not too much money. Surf the classifieds and the swap shop on this board, you can find lots of good used parts there.

Lofty

We just built a pair of 454's. Replaced rotating assemblies with a stroker kit.
Eagle Rotating assemblies (496 Stroker kit)
JE 10.4:1 pistons
Merlin "Grumpy" cast iron heads (raised exhaust ports), Team G duel plane hi rise intakes
Lightning headers
Comp cam Pt No 11-775-8,
Duration 224/232 @ .050
Lift .348/.354
Peak power is 675hp w/36 deg advance and can run on 91 with less advance but we run 110 leaded.

Nothing real special with the built except the heads where "massaged" by Tim Morgan.

Big Block Billy

The cheapest move would be get a set of closed chamber heads, have bigger valves put in them. Get a flat hydraulic cam that will not have too much overlap or lobe seperation. Add a cast Iron holley hi-rise intake , and a 750 Holley. Get the parts on e-bay. You will have to keep the revs. down below 4600, in order for the rod bolts not to stretch, and wipe out the bottom end. You would be better off finding a 365 Mag motor short block of the '91 and older variety. Like others have said, go with the 7/16 rods, forged pistons, (TRW 2399) and #7416 forged steel nitrided cross drilled crank. 2 bolt main block will be fine. I suggest Arp main studs. This equivalent of a Mag short block can rev to 5500 or more if balanced, and rods resized, with perfect machine work, assembly, etc.... BBB

KAAMA

I agree with much of what is being said here by some of the others...

My cousin's 454's engines were originally stock Merc 454cid 330hp engines. Actually, his engines are now 461cid, 218*/226* on 110* lobes, .515".515" lift hydraulic flat tappet cams, 8.6 comp ratio, dual plane hi-rise aluminum intake manifold, Holley 830cfm carbs, bowl/pocket ported GM junk large oval port, 3/8" rods, semi open chamber heads with larger valves, cast pistons/cranks. He also had a cylinder bore notch job done which is very benificial in unshrouding the valves in 454cid engine. It is usually worth about 30hp/tq. I call them "the poor man's hi-performance 330".

We used to upgrade the old Merc 454cid 330's all the time back in the 80's. Some we still used, and modified the parts it already had internally except for the cams, rod bolts. You can still use the 3/8" rod bolts, but would strongly suggest replacing the stock rod bolts with the ARP rod bolts. My cousin decided to use cast pistons, but I wouldn't recommend it. Forged pistons would be the way to go or even hyperutectic ones. When replacing the ARP rod bolts you will need to recondition the rods with those bolts and if you replace the bolts with studs in the main saddles of the block make sure you have the main saddles align honed. The 7/16" rods that come from GM are a forged rod. The 3/8" rods are not really a forged rod, but a good thing to do is have them shot peened which stress relieves them and makes them a little stronger, them have them reconditioned with the new ARP rod bolts. I have seen several guys do this in hi-perf marine applications without any problems. Over the years I have also seen several guys using the stock cast crank in marine applications up to 5500rpm.

Just make sure you have accurate machine work done with the correct clearences for a marine application engine. Also, measure EVERY rod/main bearing with a micrometer that goes in the engine, and balance the complete rotating assembly.

Anyway, my cousin's engines were dyno tested with dyno headers, and made 461hp @5100rpm and 510 lbs of torque @3600rpm and stayed pretty flat up to 5000rpm. In the boat he runs the engines with an aftermarket GIL (dry) exhaust system which is much better than the stock cast iron system. A better breathing aftermarket exhaust system like a Stainless Marine or GIL, etc, will help your engine when doing performance upgrades/mods. We could have run a larger duration cam, but with cast pistons we wanted to try and make peek power around 5000rpm or so. Using a GPS he picked up at least 10mph in the midrange, and is still testing different props---but he's very happy with the results.

What kind of exhaust system are you running?--stock cast iron Merc??? Hope this helps--- Have fun!

P Offshore

I think the 330hp is a cast crank and 2 bolt main so superchargers and high rpm are out of the ???

ECeptor

The 330 is cast crank, 3/8" rods, and cast pistons. The pistons are the limiting factor. From what I've researched, I would not put a blower on mine or rev above 4,800rpm.

The rods and crank will handle a lot more power than 330hp.

Big Block Billy

I've ran them all kinds of ways. I've tried the 3/8 rods with arp bolts. I've ran the the stock 7/16 rods. All with balancing ! Don't waste time and money on the arp resized weak 3/8 rods. Any real performance atempts in a boat, will render them poop ! Sure the bolts give the rods more clamp , but the rods still suck ! You cannot build a champagne motor on a beer bankroll ! It's like making chicken salad out of chicken S#i+...
I've been there and done that, and am still starting to begin to smarten up. Life is too short to f around to rebuild a short lived motor to get another two hundred rpm's out of. And still not be happy. People all the time are trying to make more power from what engineers spent countless hours on. The end result prooves the engineers right ! I'm sorry to let you guy in on this, but you can only get a certain level of performance from cheap parts and only for so long. Sure they could have built it better, but only did for big $$$ and still held back. !!! I don't want to see anybody have to learn the hard way. I used to think , "wow it's a 454" It's awesome. These motors stock have far more torque than anything normal. But each has it's own limitations. BBB

KAAMA

Perhaps I should clearify that these are 454cid engines in the 450-500hp range and I have yet to see 3/8" rod with ARP bolts come apart. It is what I have witnessed, and experienced since the early 80's back when we didn't have much of a choice in rods. Also, there have been times where the 7/16" GM rods have been known to have cracks around the cap areas because the material is thin in that area where the bolts are---but it's still the stronger rod. The 3/8" rods have more meat/material around the cap area than a 7/16" rod does. Whatever rod you use have them magnafluxed. I am not a rod and bolt expert, therefore perhaps they may eventually fail at some point, but from what I have seen, it has not happened to my knowledge.

Again, I'm not trying to be dogmatic here or upstage anyone here, neither am I trying to lead anyone astray----just giving testimony as to what I have witnessed in the past 25 years or so. If someone else has experienced poor results using the 3/8" rods with ARP bolts that's fine, let it be known what you have experienced here---that's what this forum is for as I would certainly like to know for myself---hey, I'm okay with correction. It's just a hobby guys, have fun.