Tired of being passed

[Ship]

Why new valve covers? Are the existing ones too high?

[Pedlyr]

One thing always leads to another. Put the new manifolds and risers on. Now I need new valve covers. Was thinking of putting the manis in the FW side but, no.

I couldnt use different valve covers on my 350. The top would hit the exhaust manifolds.

[Quik Fix]

Why new valve covers? Are the existing ones too high?

Exactly, too high. The finned aluminum Edelbrocks that I had with the engine disappeared at the engine shop. The tall blue ones in the picture hit the mani.

[My My Hey Hey]

Do you need the high ones for valve train clearance?

[Quik Fix]

Do you need the high ones for valve train clearance?

Should not. I used these rockers with the shorter valve covers before. Had this engine, with all the stock parts, in the boat about 10 years ago.

[GREGK]

If your on Facebook market place has a few. Nice looking ones in Richland for $50.

[Pedlyr]

I found that aftermarket covers where too wide. Which now makes them too high. I tried 2 or 3 types and ended up with the stamped steel originals. I have center bolt style. Need that flat edge around the base. Game of fractions of inches. I even got them to fit but they leaked

[Quik Fix]

I ordered some new, Edelbrock black powder coated valve covers. Cheaper on Amazon than the used ones on facebook. Trying to figure the cooling system now. Want to put the HE in the tub in front of the engine and the expansion tank on the engine over the circulating pump. Don't want the BIG block stock unit, even though I have 4 of them. I don't think the stock HE for 351s is enough. Might have to combine 2. What y'all think?

[Damon]

Do you think your engine will be running that much warmer? If the Johnson pump is the one that takes the bigger impeller, that’s the best! I personally don’t see why the standard stock HE won’t do.

[Ship]

Like Damon said, I don't think it will make a difference. When they size HE they don't make one for Florida and one for Maine. The water temperature being way different between them.

[Quik Fix]

I was thinking that because the big block HE was bigger, I may need bigger. I do have the bigger Johnson pump, new. Ordered a new damper from Fredwarner.net. $89 and, since I have spent a ton already, why not? Here is a tip. Don't lift the velvet drive by the tail shaft with the fork lift! Searching for a rear seal now.

[Ship]

Jerry, since the 383 uses a 350 block the area of heat transfer should be the same. The little extra amount of heat SHOULD be in HP and a little extra exhaust. Look on line to see if the factory 383s look like they have the larger HE.

[Ship]

When I rebuilt my 351 with .060 over sized rings, it increased my displacement but didn't effect my heat reading at all. I would think the 350 based 383 should be similar. I also changed the pistons which added displacement.

[Damon]

I think Ship hit the nail on the head. The volume of coolant in the block should dictate the size of the heat HE. Since the big block requires a larger volume of coolant, it only makes sense that it should use a bigger HE to cool the larger volume of coolant.

I have the aftermarket closed cooling system on my 383 from a very reputable company called Monitor, and the HE that came with the kit (it’s the same for all their SBs) is no larger than the one that was on my 351W.

It seems the factory one, which was very expensive, was smaller (I could be wrong). If you go to the Mercury Marine website, just search for the parts list for one of their 383 and you should find the diagram of one that may have measurements. The Monitor website may have info too.

[Quik Fix]

Thanks,I'm sticking with the stock for 351 HE. If I need bigger, it is no big deal to add another. Fixed the rear seal on the VD today. No biggie either,once I borrowed the BIG impact gun. Valve covers arrived. Just waiting for the damper.

[tuner]

Sizing the heat exchanger is directly related to the HP and fuel burn rate. Increasing HP and fuel burn burn increases the heat energy (small fire/big fire), and subsequently, the area needed in the heat exchanger and water flow rate. I think a standard SBC/ 351W sized HE will work with a 383, especially with a half system.