454 questions......
 

I just torn down what was supposed to be a 1989 454 mag.
I found it DOES has 4 bolt mains, but it also has peanut port heads.
Is this normal? Is it actually a MAG?
Also did the MAG engines come with an Edelbrock Performer 2.0 intake stock?

Are these heads worth using or should I reccomend the owner start looking for better heads?

Re: 454 questions......
 

330 HP engines had 4 bolt mains and small heads.

Re: 454 questions......
 

So it won't have any of the good forged parts?

Re: 454 questions......
 

The Mag has a steel crank and forged pistons. I thought it came with rectangular heads.
Edelbrock Performer Nope not stock.
Change heads - depends on what your goals and how deep your pockets are :D
I have a fresh set of 781 large ovals. PM me if you are interested.

Re: 454 questions......
 

Nope, not a true 454Mag.
By chance was it hooked to an Alpha drive?
There were a couple of years, 87 & 88 I think, that they called a 330HP/454 a Mag when it was hooked to an Alpha.
Strange, I know... :rolleyes:
Anyway, you likely have a 330HP/7.4 with flat top pistons, 3/8 bolt rods, cast crank, and peanut port heads.
Far from a 365HP/454Mag with rec port heads and forged stuff in the bottom.

Re: 454 questions......
 

Would the 781s make much difference?
The guy was planning a carb, cam, intake change and looking to be around 450 hp.
Now what is it going to take?
Things to keep in mind..... HE WILL BEAT THIS MOTOR. It will be reving at least 4500 if the boat is in motion. He was planning to rev it 5500ish WOT. With the 330 parts hold up?

Re: 454 questions......
 

454 Mag had rectangle port heads. Intakes are by Winters, same as forged the '67 435 hp tri-power vette. I have (2) original intakes and carbs with shrouds for '89 454 Mags in my storage area if you are interested in them. Redline was 5000 r.p.m.

Re: 454 questions......
 

literally building two of these motors now....

Same steel crank, 4 bolt main, forged pistion, small heads....

Installed Dart heads, "Comp Cams Extreme Marine" roller kit, roller rockers, (547 lift cam), dual plane air gap intake, and Elderbrock 750 carb gets you to 440 hp, and it runs NICE. Hits a good lick, but still VERY drivable.....

PM me if you want info, I have one off the dyno, one going on this week.....

Re: 454 questions......
 

Lots of guys build 400-450 HP engines from 330hp/454s, but it does take some work.
New heads, cam, pistons, balance rotating assembly, intake, carb, exhaust.
Most say the engine should be run under 5000rpm with the cast crank and small rods.

Re: 454 questions......
 

wt
I f you have the serial number off the tag by the starter I can run it through midas and tell you what it is for sure but it appears that you have a 330 hp. Ed

Re: 454 questions......
 

I have a 1989 330hp 454. From my research, the cast pistions are the limiting factor. Detontation will cause them to frag so be conservative with timing. I've read they will not survive long above 5,000rpm

I've heard a good cast crank and 3/8" rods built up with good hardware (ex: ARP) will live at 6,000rpm.

I'm putting 781 heads (with large 1.88" exhaust) and a Performer 2.0 intake before the season starts. Don't know what it will gain me, but hoping to see ~360hp.

Re: 454 questions......
 

I ran my 1989 330HP/7.4 at 4900rpm, 36° total advance for 120hrs. The cast pistons will melt with this kind of abuse. When I tore down that engine, 2 of 8 cylinders had low compression because the rings were stuck to the pistons. :eek:
The large ovals with larger than stock valves are worth about 20HP, but with a cam change are worth a lot more.
A Performer intake is worth about 10HP over the low rise cast unit.
360HP seems like a resonable upgrade, but if you make a cam and exhaust change the engine could make over 400HP at 5000rpm.

Re: 454 questions......
 

My cousin had a pair of Merc 454cid 330hp engines modified a few years ago. He had the engines blue printed/balanced and made sure the main saddles were correct with a align hone machining process.

Two bolt mains, cast cranks, cast pistons, 3/8" rods, aftermarket dual plane hi-rise intakes, hydaulic flat tappet 218*/226* .515"/.515" on 110* lobes, 8.6 comp ratio, 32* timing, Holley 800cfm carb, large GM cast iron oval port heads that had been modified with 2.19" stainless intake valves and 1.85" exhaust valves with some bowl/pocket/short side radius porting work done to them by JimV.

On Tom Earhart's dyno they made 461hp @5100rpm and 510lbs of torque @3600rpm and stay nice and flat up to 5100rpm with DYNO tubular headers. In the boat the engines have been installed with some DRY aftermarket GIL exhausts which will lower the HP by probably about 20-35hp or so as compared with the dyno header power numbers, but he is very impressed how much better/faster his boat now runs with all the mods he has done.

Re: 454 questions......
 

I have a fresh set of 188 heads for sale {Rect,Open chamber} Inconel-stainless valves. ports cleaned up & chambers

Re: 454 questions......
 

In my 1990 251 I had Rectangle heads. Not sure if they where stock or some one added them . One went bad. Put on 049 heads. Idle improved tons. top end stayed the same. Ran good at 5k till the cast crank broke

Re: 454 questions......
 

Cam, exhaust, Performer RPM, forged pistons, ARP bolts, and a bottom end freshen/check are the next step...hopefully next winter.

Head change was due to a crack in one of the stock peanut port heads. The upgrade to the 781 w/ large valves ($100 from a friend of a friend) was a lucky upgrade.

Re: 454 questions......
 

I had a 87 Velocity with the 454Mag 330 HP strapped to an Alpha. I think it was 89 that they came out with the 365's

Re: 454 questions......
 

So would this thing make any power with forged pistons, 188 heads, a bigger cam, and a holley 800?
HE HAS exhuast upgraded and roller rockers on the old heads (if I need to swith them I will)
OR
what is this motor worth to sell all freshened up? It ran fine but "used" oil. Oil loss was a leak around the oil filter relocation housing. He decided motor was out so lets build it...........
How about a whole motor transom plate bravo 1 package with freshened motor and Bravo with 300 hrs. what is all of it worth?

Re: 454 questions......
 

EC, sounds like you got a good deal---especially, if they had the larger valves installed. Usually when larger valves are installed that the bowl area has to be enlarged a bit. If you can check the short side radius and make sure they are nice and rounded with no sharp edges or turns. Check to see if you have the hardend valve seats installed when using stainless valves or they will end up sinking within the head---it happened to us way back in the early 80's and if I remember correctly it was mostly on the exhaust side. The forged pistons and ARP rod bolts are a good idea, and if you can have the rods shot peened---might cost about $50 per set or so. Have fun.

Re: 454 questions......
 

Another question......
How would a B&M 250 work with hypereutectic pistons better rod bolts some new bearings, some balancing and some beefier bolts to hold it all together? STOCK CRANK AND HEADS
Could it make good power using the stock peanut ports (for now)?
Would it hold up provided it doesn't get revs too high..... 5000ish?

Re: 454 questions......
 

You must be talking w/ my "engine advisor" buddy...he told me the very same thing. He said mag rods and crank, shot peen rods and put in good (ARP) bolts then top it with forged pistions for a short block that can live up to 6,000rpm easy enough.

Re: 454 questions......
 

EC....Well, contrary to what my cousin asked me to use he still used the stock rod bolts, he didn't shot peen the rods, and he bought new CAST pistons. I tried to talk him into the better components, and I warned him of the chances he was taking, but he only had so much money and they're not my engines so, during the rebuild he at least he had good, accurate machine work done by a reputable shop that is used to doing lots of offshore marine stuff. Also, we at least we proped and cammed the engines to only peak out at 5100rpm when using stock 3/8" rod bolts and cast pistons. So far he has about 35-40 hours on the engines and everything is fine. Hopefully everything will stay that way, but remains to be seen.

Anyway, making sure the block is "square" is where it all begins---especially align honing of the main saddles, and balancing the rotating assemblies just to name a few. I hope you have fun with your project.

Re: 454 questions......
 

I already have my shop picked out. Same shop the +7,000rpm guys use. He has a backlog of work, it's the cheapest in town, but I've been told his work is 100% spot on every time. Slow, careful, accurate...

It's fun to plan, will be more fun when I finally get to it next fall!

Re: 454 questions......
 

I have a 454 385hp question.... Whats the best cam to run with emi thunder exhaust and risers?

Re: 454 questions......
 

I forgot to mention that he has a 1988 32' Baja and didn't know how fast his boat was with the stock 330's (he didn't have a GPS at the time), but AFTER he did the mods to the engines and using the SAME props (21" 3-blades) as he was using when the engines were stock 330hp, he could tell the boat was faster and much more responsive than it was stock. So, he really picked up some speed when he went from the 21" 3-bladed props and tried a 25" 3-blade as a test and picked up 10mph in the MIDRANGE on the GPS---so far, 69.8mph (top end), but they're still experimenting with props. He cruises with it mostly somewhere between 3500-4000rpm and he seems to be pretty happy with the way it runs since the mods.

Re: 454 questions......
 

I am in the process of building a gen V 330 hp I am having the engine bored .030 over forged pistons domed 8.79-1, moly rings, a balanced assembly, all bolts are arp, melling high volume oil pump, dart merlin oval port heads 2.19/1.88, 117cc chambers ported and flowed, running a crane 420 cam, crane billet steel timing chain, crane gold roller rockers, eldelbrock intake and 750 carb, revolution marine exhaust 4in hose and tips no mufflers, and a msd ign. I hope it will run much better it is a wellcraft nova spyder 23. I ran about 60-62 last year running a Bravo 1 24pitch

Re: 454 questions......
 

k24u, Sounds like a really nice combination with the mods you have selected to do. However, I'm not that familiar with how well the Revolution exhuast system flows compared to something like a GIL or Stainless Marine aftermarket exhaust system, but with the mods you have listed above I would say you should see 70+ MPH by the time you're all done tweeking it in with props, etc. Have Fun!

Re: 454 questions......
 

WhenI get her together i will post how she runs as long as it is strong and dependable I will be happy

Re: 454 questions......
 

If he will spend for a blower , spend the money and build a good motor once and put the throttles down all day. Wrenching is work , Boating is relaxing.

Re: 454 questions......
 

Its going to be a N/A motor........

We found stock 454 mag Crank and rods locally. Boring .030 and buying JE pistons (100 dome) Edelbrock Allum. oval heads, RPM Airgap intake, Holley 800, a cam (not exactly sure on part # for that) and all new bearings seals etc. Should be a nice upgrade.....