Need to replace 1972 HM 302 exhaust manifolds

[72Sweet16]

Hello all . . . it seems I find myself needing to replace the exhaust manifolds and risers on a '72 HM 302 in a 16 Ski Sporter. I've just finished an engine re-build due to bad winterization/frozen block (thanks to all who helped in that thread) and now it turns out one of the ex manifolds is cracked as well. The pics aren't very clear, so if I need to provide more info just let me know and I'll give it my best shot.

Can any of you guys point me towards some sources, i.e. mfg, model nbrs, distributors, www sites, etc.? I'm hoping to just get her back in service, not necessarlily the latest/greatest thing going . . . . or does anyone have a "known good" set of them laying aroung they want to get rid of? (to the moderators - I'll move this portion to want ads if needed)


THANX !!

[mattyboy]

the holman moody risers were made by glenwood I believe, search holman moody and glenwood on ebay another option would be barr or osco center risers . just watch the height of the risers

[joseph m. hahnl]

the holman moody risers were made by glenwood I believe, search holman moody and glenwood on ebay another option would be barr or osco center risers . just watch the height of the risers

http://www.glenwoodmarine.net/Catalog.htm

[thescooter]

i haved used OSCO

[Gary S]

What is actually wrong with yours? I see a chip out of the mounting surface,anything else? Now that I look closer it must be a shadow.

[mattyboy]

Barr marine for Fords

[72Sweet16]

Hello all,
Sorry for delayed reply - had to go out of town and had no access. Appreciate the suggestions, I'll try and look 'em up this evening. As for the problems mine have, apparently they suffered from the same "winterization/freezing" problem as did my block; i.e. there are internal cracks. When tested, water flows out the exhaust ports . .. ..

Tx again, and I'll be checking into glenwood, osco and barr this week.
Any specific limitations I need to worry about? especially w/riser to transom fitment?

[mattyboy]

you'll need some wet exhaust hose if you go to the center risers. with your end riser logs there is a short piece of hose that attaches to the tips. the center riser dump is more towards the middle of the motor so that hose to the tips will be longer. you'll need to double clamp both sides of the hoses. the barr and osco come in 3 and 4 inch some of the older boats had smaller tips so you'll have to see what you have. I just did this on my boat I removed a jury rigged capt call system and had 3 inch center risers going to 4 inch tips. There are a bunch of adapters to help get the job done.

[72Sweet16]

OK guys . . . finally got time to check out some of the suggestions. I started Google-ing Glenwood and Barr, then found Osco. Looks like Osco not only mfg's some of their own, but is distributor for the others as well? I found them at: http://www.oscomotors.com/index.asp

So, on their site I found four candidates for Ford 302 - for both center and end risers. Other than fitment issues, i.e. overall height and length, I'm truly clueless as to pros/cons of either style or of any brand over the other . . .. . other than price of course. If you guys are familiar enough with dimensions to steer me in the right directions, it'd be really helpful - my new engine is still out of the boat, so I have know way of knowing if any of these will/will not clear the deck lid and provide enough room to connect to the transom ports.

sorry for the .pdf's - (I didn't have a way to convert 'em to .jpg's) - but they do scale up well.

THANX !! to all

Clark

Oh yeah - if anyone can recommend a supplier w/reasonable prices, that'd be cool, too.

[mattyboy]

you are going to want to stay away from the pleasurecraft risers they are for a ski boat with low exhaust exits the mercruiser ones are end risers similar to what you have now the end risers can be hard on the valve train on the back cyls. the osco with the 3 inch exhaust riser with no spacer should bethe ticket . the osco have a stainless insert and a short extension seen in the pdf which means the water and gases mix in the hose not the riser not sure the barr are the same

But if it were me I would get the motor in then take some measurements before getting the risers. this way you can find wether the 10 or 30 degree angle works and that they will fit under hatch.

here is a shot of osco's on my 302

[mattyboy]

here's a shot of a 1970 16 with a 302 and newer center risers so they should fit. these look to have very low or no thru hulls so making up any angle out of the risers is fairly easy
http://www.donzi.net/forums/showthre...-Sweet-16-1970

[72Sweet16]

Scooter - thanks for pointing me towards the Osco site.
Mattyboy . . as always, appreciate all the good input. And especially the pics; glad to know the center riser style can be fitted in. I got a lead on a pair of "older ones" that are local to me earlier this week. Supposedly they are some flavor of MerCruiser and are end-riser style. Fellow says he'll water/pressure test 'em this weekend, and if they're "OK", then I'm planning on taking a look by mid week. As for getting the engine back in before before hand, that seems to be very sound advice. I will take one of my old ones w/me when I go check on these candidates.

Any specific things to watch for in a pair of "older" MerCruisers? I'm hoping that, when compared side by side, I should be able to get a pretty good idea as to fitment . . .

BTW, the guy has offered this set at at $200 bucks including risers. At what point would you guys say Nope - just go ahead and get new ones? I didn't chase down all the prices for the ones I listed, but I did price a set on the Glenwood site at something like $1,500 plus for a pair w/risers. . .. .. that's a bit much for me, seeing as how I got the engine re-build for only $1,600 - that makes the $200 sound really good (but I haven't seen them yet either).

THANX !!
Clark

[silverghost]

I would bet that those "Mercruiser" manifolds you are talking about locally will NOT fit your HM FORD 302 engine.

I suspect they are for a Chevy engine.

Mercruiser never built manifolds for any FORD application that I know about.


Why put old Marine manifolds of an unknown age & condition on a new rebuilt engine ?
Too risky in my opnion~~~just to save some money.

[mattyboy]

I would bet that those "Mercruiser" manifolds you are talking about locally will NOT fit your HM FORD 302 engine.

I suspect they are for a Chevy engine.

Mercruiser never built manifolds for any FORD application that I know about.


Why put old Marine manifolds of an unknown age & condition on a new rebuilt engine ?
Too risky in my opnion~~~just to save some money.

SG~~

Merc had the 188 and. Higher HP pkg the 233 i think all mated to one of their drives the drive was called the 888. This was in the mid 70s. Both of these used the ford 302 as a powerplant. That's why osco lists a merc end riser replacement pretty popular pkg.
http://www.donzi.net/forums/attachme...1&d=1336607200


there is a hm 16 for sale out on the island right now which has a 188 replacement motor in it. I believe Forrest Colie (sp) here also has a ford merc original factory 16 that runs very well left handed and all.

here's a vid of a merc ford setup with the stock merc end risers they also made a 255 which was the 351 as the powerplant unless merc moved the dist on their chevies??????

http://www.youtube.com/watch?feature...ne5x60VoY&NR=1



72

I think if you shop the barr center riser you can get them at around $300 a side new plus maybe around another $100 for hose and clamps and the little things . The used end risers may be ok but how long might they lastis the real question. plus I would be worried that they won't quite line up with the old ones and now you don't have enough room to make up the difference. rigid exhaust hose is a bitch to work with if you can get both sides for 200 and they test ok that is not a bad deal and if you had to re sell should be easy to get off your hands

[mattyboy]

72

one more thing, make sure the mercruiser end dumps are straight out and not the ones with the downspout. the true value of the used ones might be only to get you thru this season. I would not look at them for a long term solution.

hope this works out for you