Persuader261

Hey guys,

Im hoping some of the engine genuises on this site can verify a rebuilt engine build sheet. The guy who built the engine is an old timer who seems to know his stuff. When I looked at the engine the gaskets were fresh, everything was clean, and it ran on the stand. He claimed this is a reliable build for ~400hp that he has been doing for a while. The specifics are:
1. Chevy Gen 5 4-bolt main block bored .030
2. GM Standard Nodurlar steel crank shaft with Clevite bearings
3. Speedpro 200cc domed pistons with Moly rings
4. Forged 6.135 connecting rods
5. Chevy oval port 781 cylinder heads with stainless valves 2.19 and 188
6. Howard high performance marine hyd flat tappet camshaft .527 and .533 value lift
7. Howard high performance valve springs
8. Heavy duty 3/8 push rods
9. Competition roller rocker arms
10. Aluminium tall valve covers
11. Edelbrock dual plain intake manifold
12. Cloyes double roller timing chain
13. Mellings high performance oil pump
14. 8qt marine oil pan

Any input or confirmation of the above build and what power it should produce would be very helpful.

Thanks,

Mike

Persuader261

The carb, ignition, exhaust, and accessories will come from my stock 454 Mag.

f_inscreenname

Sounds kind of snappy. Did he have it balanced?

DMOORE

only thing i might want to change is:

#11 id switch to a single plane I have just had better performance with a single plane due to where boats seem to live RPM wise

Griff

Chances are your stock carb and exhaust will not work or at least not work well with it.

It probably is a decent 400hp engine. Reliability depends on how well its put together.

glassdave

iTrader: (1)

what single plane intake would you recommend and what do you think about an Edelbrock air-gap dual plane in that low HP range? Just curious, i had a couple old 365 Mags in an old ScarabIII i was playing around with at one time. Still have the Mags that a friend may put in a 30 Formula and they need freshening. I had always thought in the mid four hundred range the dual plane would be happier and help torque better. Again in that low of an HP range. I had also heard there is a bit of an advantage to running an oval port manifold on the square port heads.

MILD THUNDER

iTrader: (3)

200CC domes?

Nodular Steel? Its either Nodular Iron, or Forged Steel. I'm assuming its a Nodular iron crank, better known as "cast crank".

350-400HP sounds reasonable, depending on the actual compression, and camshaft specs.. . Like Griff said, how it was put together is the key, as far as reliability goes. I see no big benefit to a single plane, as I'm assuming, the engine isn't going to be run north of 5,000RPM, if still using the stock 3/8 rods that came with the cast crank setups. .

SB

iTrader: (1)

A few people on OSO have proven the vic jr beats the air gap rpm in even 400hp 454's.

Yup, would have never believed it either. Bunch of tests where run in the boats before and after.....Wideband's to tune each set uo and etc, etc.

Dyno won't agree...but apparently this is where the saying "We don't race dyno's" come from.

I'll see if I can get one of the guys to chime in here.

SB

iTrader: (1)

Mike, not enough info. We need all cam specs...lift doesn't tell us a whole lot.

The real compression ratio is very important too.

Manifold would be good to know what model of Edelbrock.

And we can never guess for the tune of the engine, which can make or break an otherwise good motor.

Sonic30ss

Interested in this- debating/researching this choice now