GM 454s or Gm 427s?

Rocky · Post by **Rocky** » Dec 3rd, '08, 01:36

Not to beat a dead horse here guys, but when I inquired about what original manifolds the Bertram came with from Mercury/Mercruiser's serial number on the I.D. tags at the bell housings, Mercruiser told me my serials match GM 427s. He also said the manifolds were the "log" style that those engines came with. Well, somone put center risers on them and consequently now the boxes do not clear. I pulled my rudders, shafts and couplers off, and see even wear around strut bearings, and logs look O.K., so alignment was not a problem in the past. I think I want to leave engines were they are if alignment measurements are O.K., and buy the correct manifolds. Anyone have other suggestions? I'd appreciate any inputs! Rocky.

Harry Babb · Post by **Harry Babb** » Dec 3rd, '08, 08:30

Sounds like a logical plan to me.

I believe that the seawater (SALT WATER) cooled manifolds have a life expectancy of 7 years or so.

If yours are aged and seawater cooled you may kill 2 birds with one stone! ! !

Harry

John F. · Post by **John F.** » Dec 3rd, '08, 08:42

Sounds like a good plan. Spray everything with Corrosion X so that the manifold and riser bolts come off a little less hard (I don't think they're ever easy).

I have the log-style manifolds on my 454s--I wondered if center risers would fit...

When I replaced my risers/elbows, the prices at the local merc. dealer/parts guy were very close to anything I could get online, so I bought there. Just a thought--the online guys don't always have the best prices.

John F.

randall · Post by **randall** » Dec 3rd, '08, 08:52

check the manual for torque on the manifold bolts. i was surprised at how low the number was. this season for the first time i have a very easy fresh water post run rinse out set up....dont plan to change my manifolds for a looooooooooong time. something to consider.....especially with mercs.

Rocky · Post by **Rocky** » Dec 3rd, '08, 09:39

Thanks for the tips guys. About the manifolds on there now, they are unfortunatley brand new by original owner! Rocky.

bob lico · Post by **bob lico** » Dec 3rd, '08, 09:59

rocky you may have hit the jackpot .look at the rear top of the engines.there are a raised embossed set of numbers tell me the last 3 numbers.should be 642 or 351.looking from the flywheel end the numbers would be on the the top left bank (cylinders 1,3,5,7).

Harry Babb · Post by **Harry Babb** » Dec 3rd, '08, 12:34

About the manifolds on there now, they are unfortunatley brand new by original owner! Rocky.

EBAY!!!!!

Tony Meola · Post by **Tony Meola** » Dec 3rd, '08, 21:59

Rocky

Be sure to get a price on Merc risers and logs. You might be suprised and find them closely priced to the Osco's and Bar's. Several years ago when we put new risers on, they were the same price as the Osco's. Also, there was a spacer between the riser and the manifold on the old style logs. That was to give the riser another inch or so of height just in case. You don't really need them but you may need to change the plumbint a little bit. Might mean adding a hose.

Unfortunately I don't remember if it was fresh or the salt side, maybe Bruce knows. My engines are long gone so I can't even check it out for you.

Rocky · Post by **Rocky** » Dec 4th, '08, 01:03

Hi Bob, yes I did get those numbers, 10063286 same #'s on both engines.Our parts guy at my work (Toyota dealership, I'm a tech) is a car racer and really knows big blocks. He said the only difference between the 454 and the 427 is the stroke. Everything else is the same right down to the heads. Unfortunatley Mercruiser shows discontinued "log" style manifolds! By the way, when I took just the risers off the inboard sides of engines, boxes clear.This is driving me nuts. Rocky.

Bruce · Post by **Bruce** » Dec 4th, '08, 06:25

The Barr manifold web site lists log manifolds for Merc.

Get the numbers you need from the pdf listings and then internet shop for your best price.

Rocky · Post by **Rocky** » Dec 4th, '08, 10:08

Thanks Bruce, maybe I'll actually get to launch this thing some day! I do have to rebuild rudder shelves as well, I printed out Capt. Patric's procedure on the two piece design due to the Hynautics ram, I cannot do the one piece going across. Someone (hack) had put 1/2" "marine" lumber in as shelves holding bearings on top of rudders AND holding the forces of the stationary end of the ram! I would'nt think this is safe.Would anyone know were I can purchase the rudder shelf bearings, strut shaft bearings, and the best packless shaft seals for 1 3/8" shaft? I am not going diesel just yet , maybe when I win the lotto. Rocky.

Rawleigh · Post by **Rawleigh** » Dec 4th, '08, 10:14

I have the PYI shaft seals on my 1 3/8" shafts and love them! Bleed cooling water off of your heat exchanger if you are fresh water cooled.

CaptPatrick · Post by **CaptPatrick** » Dec 4th, '08, 10:47

To further Rawleigh's comment, there IS no better shaft seal than PY!/PSS. Period. You can order directly from them at 800-523-7558...
Details of the seals are HERE.

Bearings can be had through WW Grainger...

Br,

Patrick

Capt Dick Dean · Post by **Capt Dick Dean** » Dec 4th, '08, 11:07

A few yrs ago I had to replace the log type manifolds and a shop on Long Island said now was the time to switch over to the new type. Well I didn't. And now I'm glad I didn't. I never thougt of the head room for the engine box.

Anyway, I asked the manifold guy about the spacers between the manifold and the risers. He said he would have to make them when the risers are changed. It's that time ... I might get one more season on the risers.

So where can I get four spacers?

bob lico · Post by **bob lico** » Dec 4th, '08, 15:16

rocky 351 as the last 3 numbers would indicate 1967 corvette 427 worth about 14,000 just for the core would give you brand new 454 mercrusers for them.

Tony Meola · Post by **Tony Meola** » Dec 4th, '08, 22:20

Dick

As I noted above you can eliminate the spacers, they are not really needed. You will not find them, 3 years ago I all over and only found one. Its a futile search, trust me.

Rocky · Post by **Rocky** » Dec 4th, '08, 22:28

Thanks guys for the info. Bob, you had me scrambling for my wallet after you gave me that info about last three numbers being 351, as I forgot exactly what #s I had. Thanks a lot. Whish I did have 351 ending numbers, it would have paid for boat!! Rocky.

bob lico · Post by **bob lico** » Dec 4th, '08, 22:33

year like the lotto a pair of 351 blocks will fetch 28,000.just one call to corvette n.c.r.s and there would be a truck at your door and a machanic to install those 454 mercruisers.i am not kidding to die for!

Capt Dick Dean · Post by **Capt Dick Dean** » Dec 5th, '08, 10:27

Tony,
O.K., thanks. Now I'll never know how much I've saved.
Being part of this website is great.

Tony Meola · Post by **Tony Meola** » Dec 5th, '08, 21:28

Dick

Just remember, you still have to plumb a hose to the back side of the riser to get water up in there.

Rocky · Post by **Rocky** » Dec 5th, '08, 22:42

I bit the bullet and purchased the PYI PSS shaft seals today. Ouch! Oh well, they won't drip, or need maintainance.Thank you Capt. Patrick for the advice, I think that was a good upgrade. About those manifolds, especially for Capt. Dick Dean, I took the risers to a machine shop and had them put a 3 degree angle on surfaces toward center of engines, and wa la, they clear boxes by conforming to the shape of the inward turn the OEM boxes have! (40$). Rocky.

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GM 454s or Gm 427s?

GM 454s or Gm 427s?

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