fastscarab22

iTrader: (1)

If you want you can get set of hp 500 heads , with the heads done for $ 600.00 or so ( htg racing on this site) new head gaskets and intake $ 150.00 . Then do a leak down and go from there . This way you know the heads are good and no waiting for machine shop and the unknow from them . a couple of hrs and it done

thomas_e102

That sounds like it would work for me fastscarab22. I went to there web site and i saw alot on sleds but not marine heads. I guess I could just call them.

fastscarab22

iTrader: (1)

Robs cell is 716-418-6131

thomas_e102

ok good news is I think Ihave a Gen IV motor. SN# OD819646. Engine builder In northern IL said I might have a "Bow Tie" motor. What is a bow tie motor?

fastscarab22

iTrader: (1)

Look at the chevy logo, looks like a bow tie

thomas_e102

Where do I find it on the motor? What does a bow tie motor mean I have? Is it a big deal?

rjr

He's pulling your chain they are all Chevy's

Boat1

A Bow Tie block is GM Performance block. It will have an embossed bow tie emblem on the side of the block by the freeze plugs. This would make it a Gen 4 block, it is a high quality block well suited to performance applications. The only drawback I see is that Gen 5 or 6 heads cannot be used on a Gen 4 block due to water passage issues with the cylinder head. A Gen 4 cylinder head can be used on a Gen 5 or 6 block. You mentioned engine builder, is this a mercury marine engine or a custom? If you do not see a bow tie emblem on the block, then I would feel just in front of the oil filter pad on the block next to the oil pan rail. If you feel two threded plugs in the pan rail just in front of the filter pad you have a gen 5 block. Both Gen 4 and Gen5 blocks have 10 bolts in the timing cover, visually they are similar unless you know exactly what to look for. You need to figure out what you have before you decide what your doing.

thomas_e102

Boat1 thanks for all the info. Bill over a ateco looked up the numbers and he said it takes to 2 piece rear main seal. that makes it a IV. I will look for the plugs in the oil pan. I see one in a photo i took port side of pan about dead center in the pan. If I had to guess 1/4 to 3/8 head.

2Slow4me

Did you do a wet & dry compression test??

My understanding it if the numbers change after squiting oil in the cylinders, than your rings are bad (= full rebuild)

and if no change it is your valves.


??? leak down test showed #6 60-75% leakage and #1 10% leakage. leaking from intake.


How does a leak down test work? And what do those numbers represent? What would the numbers be a brand new, or fresh rebuilt motor?

And if buying a boat, is that the best way to test the engine (besides driving it)