chevy II 153 four cylinder

I really like what you did there if my forklift manifold does not pan out I may copy a bunch of that .
A few of the VW manifolds on Ebay I see.

I was thinking of a pair of Harley carbs also

 

It looks like a pair of Weber IDFs would work on the forklift manifold. I'm still working on my manifold for DCOEs on a 181 head.

 

Mahle HS5719W MerCruiser Marine 3.0L 181 Head Set Gaskets Later Model | eBay

Note the two different intake gaskets for the 181. Mine gasket is the bigger port one but the actual port is bigger than the gasket.

Also the bolt pattern appears to be different unless there just flipped around

a
so there must be two different 181 heads out there and one obviously has bigger ports .

 

Fel Pro 17302 Mercruiser Marine 3.0L 181 Intake/Exhaust Gaskets after 6229717 | eBay

Note the after S# 6229717 this gasket is similar to mine.

 

Mercruiser 3.0 Parts | PerfProTech.com

Once the 2.5L engine model was discontinued MerCruiser did in fact offer several versions of the 3.0L engine; one the however being the 3.0L "L" Series Engine Models and the other being the 3.0L "LX" Series Engine Models. The 3.0L "L" Model engines utilized a cylinder head with larger ports whereas the 3.0L "LX" models utilized a smaller rectangular port cylinder head. In approximately 1995-1996 time frame the MerCruiser 3.0L "L" model was discontinued for the 3.0L "LX" model and became the only 4 Cylinder Sterndrive Engine option offered by MerCruiser going forward.

So there is a big port L model and a small port LX model .

Apparently the O the OMC engine has a big port MC engine I have is a big port of some sort also

 

Replacing the Mercruiser 2.5L & 3.0L Engine's | PerfProTech.com

GM produced 2 different 3.0L model marine engines up through 1994. They were both 3.0L Marine Engine models but had different cylinder heads which is where they got the different performance levels; 120 (large oval port head) and 140 Hp (small rectangular port head). They however do range the ratings on them so you could have one version that was previously rated the other version in previous years. Starting in 1995 all that GM produces is the 140 Hp longblock. The new 3.0L longblocks are offered to be used as a replacement either way for which ever version of the engine that you have.

So the big port is the low HP verson hmmmm that makes little sense . wonder why?
20 HP differance based on just the port size .

I always thought the 120HP mercrusier was a 153" and the 140HP was a 181"

 

I think there were 3 181 heads, maybe 4. I think the very early ones were like the 153.
I took the long way around on my Mallory. If I hd known more it would have been easier. They actually made one for the 153 but they are hard to find. There is a ton of interchange in the old Mallory dual points. Just about everything can be mixed & matched. I'm no expert but there part numbers out there.

 

LOL- just finished emptying the storage unit from when we moved a couple years back...
COMPLETELY FORGOT that I pulled a complete 153 Mercruiser out of a great old (now gone) local yard!!!

 

ck w/impco propane guys. they have adapters for carbs also, but might be from rather than to
Here is Nash listing
https://www.ecrater.com/p/21051310/impco-original-7152140-right-manifold-gm
or a Weber if you can deal w/Brazil

 

That is about the same manifold the earlier Hysters and Yales use say form about 2000 and before and hey Runa a very basic Impco LP system no electronics jsut a LP regulator and mixer / carburetor .

I have one customer who has a Hyster with something about like that . I had the head off a few years back ( thats when I realized hey this is a Chevy with a Chevy bell housing pattern and started reading up on these engines . I was hoping to get my hands on that engine when they retired it and the damn scrapper beat me to it . I know it had smaller ports and there was 8 of them

My source if it plays out is not Impco . Im going to have my parts guys see what he can get that manifold for . I can get it about dealer cost if its available . I have installed 1000's of the impco stuff over 41 years of working on lifts and such .

What Im noticing on it is the small ports like on the later MerCruiser .
Im startng to think the industrial motors have smaller ports and such to give the power they need in the lower RPM range.

I think I know were a later Mercrusier head is thats cracked with the smaller ports that is the only one they sell now that I can get free . I may take it and my 1987 OMC 181 head that is advertised also at 140 HP and have them flowed . I have a buddy with a flow bench . It would be interesting to see whats what and compare to a 120 HP head or the original 143 car head with mods .

The parts for these are reasonably inexpensive around here and if im going to do this id like to get the best head that available on the boats .

If im giving up 20 HP according to the boat link i posted with the big ports then im going backwards .

Im wondering if the small port newer head has a better combustion chamber and stuff like the Vortec has over the earlier SBC stuff ?

 

On the Mallory I just skimmed over it . Did you use a Pontiac distributer because it spun the other way ?? I had thought about the 4 lobe with one only set of points made to fit from a chevy as I have a couple but if a chevy will not work then I'll have to start shopping.
figures a guy had a box of like 20 of the early Mallory's at the Jefferson swap meet last weekend . I did not got through them.

 

I looked at this a few years ago and they sell manifold adapters for old intake on new head
https://www.michiganmotorz.com/mercruiser-exhaust-manifold-adapter-plate-kit-high-output-3-0l-engine

 

pretty sure that’s the same Intake that’s on mine. Never considered it being an industrial only intake. It had a schebler side draft on it I believe. It was a power unfit motor with a big drive pulley set up on the back of it. Regulator and the whole gig. Had wondered if it was a propane set up mainly because they -apparently- should have the 307/flat tops giving the highest compression ratio

 

(PDF) IMPCO 2011 3.0L GM Engine Emission Certified Natural Gas/Propane Fuel System for Stationary Power Generation Venturi Series With Fuel Selector Service Manual | Natan Hernandez - Academia.edu

Some other Impco options . 3/4 of the way down inhte parts section
part number 5152141 for int and 7152150 for exhaust . I think this is water heated intake also

 

I wonder if thats made from cast or just milled bar stock ? If it's just steel, it could be welded on and have the intake be part of it .

Good to know it exists. I guess if I build stuff for what I have and find a better head later I can always use what I find now or make on the new ( maybe better head ) .

the exhaust port are like half the size of my head and the intakes are much smaller.
Im wondering if this is a midrange HP thing and the big port makes more with a better intake and header?? Bet there is some midget guys who would know the story on these.

 

Impco 7152150 Manifold - (gm 3.0l Right Exhau) :TruPar.com
$400 exhaust manifold option
its going to be pretty low performance as in a 1 3/4" outlet or so.

 

Maybe some sort of lumps in the big port head are in order ?? the bottom of the port it pretty low like the 153 car engine and 120 HP 2.5 boat and the 250 sixes that get lumps added ??

seems like that big exhaust port would be a plus ( especially with a header) the intake is were they really went smaller for some reason.

Trying to find a combustion chamber comparison

 

I built a header from a sbc build your own set of tubes and a plasma cut 250 6 cylinder flange cut down

though depending on your intake a sbc could be made to fit really easy

 

Welding heat warps the material and will have to be surfaced to hold the gasket seal

 

I was just out in the shop looking at the cracked 3.0
Took me 11 minutes to get the head off.
Shame it's cracked I bet this engine did not have 50 hours on it.
Valve train looks new. Head and valves look OK but I won't know until I get it magna fluxed .
No carbon , no oil standing on the rockers , push rods still shiny .
Ring gear had zero wear .
The fly wheel in it looks like it would accept a clutch its drilled for a pressure plate it appears and since it's in a boat it's never had any use .
If the bottom end is as nice I need to find a way to use it. It does have dish pistons . Judging from the near perfect bores I bet the pistons are good.
I answered a ad for a 3.0 bare block on market place haven't heard back .

I had a SBC with a set of really big port RHS heads for a 413" SBC sitting on the stand so I over layed my 3.0 gasket over the RHS ports .
Like you said the pattern ports are really close .

The 4cylinder ports on the exhaust are huge . A standard chevy header tube would be small but in sure it would work .
I'm thinking one of the lakester header kits and a heavy flange would be a easy project . I have TIG, MIG, mill and all that .

A adapter plate like for the VW set up above and i could run a sort of SBC spread port flange set up with three bolt in the middle .

 

Went into the intake port and removed the bolt/stud boss, then used a counter bore to dress the seating area and tapped the upper hole (access to the intake bolt) for a pipe plug. Blown deal, dont need to worry about flow numbers of individual ports/runners

 

couple more pics

 

I chose the Pontiac distributer because it was a good shape to make it fit the Chevy 4-6 and it has vacuum advance, something none of the Chevy 4-6 bodies have. The stock external vac advance might work. The one I used is a Dual Life. It has two sets of points but only 4 lobes. Each set of points fires 4 cylinders.
Then when I was putting it back together and was making a longer shaft I remembered the Pontiac turns the other way. The lobe can turn either way. The point plate had the LH part number on one side & the RH number on the other. The mounting tabs would have to be re-bent. The weight plate has the same number setup & could be flipped but the pins would have to be removed and put on the other side. I'm not sure if the weights can just be flipped or not. I ended up using the 4 point lobe from the Pontiac and the rest of the guts from a Chevy V8. I shortened the V8 shaft & used a 6 cylinder gear. Broken & partial Chevy v8 Mallorys are plentiful. The hardest part to find is an old style two part Mallory 4 cylinder cap, an 8 would work. It didn't go this smoothly but it should have.

Easiest way: 1. Find one of the rare four cylinder ones. I'm not sure there was an old style. 2. Put the Dual life 4 point v8 lobe in one of the early Chevy-GMC distributers. There is a small difference in how far the distributer sits in the block on the old (pre 194-292) & GMCs. The 153 is the same as the newer sixes. I can't remember which way it goes right now but I think the old ones sit deeper and can be used in the newer blocks with a small spacer. This would not have vac advance unless the external stock style advance was used. This might take care of the depth issue.

 

OH MY this is going to be good . Blown and injected .

 

Ironically I got a call on a JLG boom lift and this was under the hood .
that lower intake is just screaming for a pair of down draft Webers or simular. Might even be the correct bolt pattern it's three bolt per side.
No cross over on it how ever and no heat . Cast iron and heavy but man it looks good.

Exhaust will hit fire wall as is I'm afraid unless engine is moved forward . Might be able to cut it and 90 it down or at and gain a few inches .
I'll be able to get a part number at the least . I have the machine model and serial .

 

While we are at it a model A intake almost fits these as well. I’ve seen them used with plate steel adapters but looking at one in hand it seemed like you may be able to just slot the holes

 

1biggun, that is cool and it has been there when people were looking!

 

My guy is pretty confident he can get me at least one used intake top and bottom and one bottom dump exhaust used and possibly the rear dup exhaust and the intake new .
He sent me pics today of the used stuff on a engine and said "cheap" if used was ok.
I said hell yes and BTW grab everything else you can get

Im looking at my pictures and thinking the ports might be a little to close together for a Weber DCOE down draft without a thick adapter to blend to to fit . They make some manifold flanges cheap ( ebay ) in both steel and aluminum for those carbs . If I can just bolt one down then thats path to go .

A pair of Rochester 2bls might work one barrel per cylinder if the spacing is close then thats a option also . Cheaper and easier more old school . would be no balance tube however but Im contemplating drilling a hole clear through all four runners and putting a line in between the center and then plugging the outside or having a vacuum port
How important is a balance runner on a set up like this ?

Somewere in my mess I have 3 or 4 stock carbs off a 235 or smaller chevy 6's . A pair of one barrels and some old school little air filters from the 50's I have would likely run the best .

I have been staring at the big aluminum top half going over the valve cover and first thought was its ugly but then I started thinking if it had a side draft or two on the RH side of the engine if I milled the face off and welded in a plate and polished it up it might look OK . Then I started thinking a Eaton or 371 blower on top of the valve cover or on the RH side feeding the top half of that manifold .


A turbo on the left through a intercooler in the grill to the right side and over the valve cover might be doable but a bit to new school for my project .

Looking at the aluminum top I see the runners spread out . I could mill it back to just were the runners stop weld in plate and bolt on one or two side draft webers ,
Harley carbs , 4 motorcycle carbs or anything else and have it all be about directly over the top of the valve cover and pointing to the right side .

Once I make this worth his while I'm going to ease into the so how do we get more for others conversation . I will be getting part numbers however for sure .

I just hope this stuff fits on my large port head somehow .

 

Get 'em, send 'em to CNCDude or twisted six, make a deal, stand back!

 

posted on the HAMB a long time ago that French Lake auto parts cast some exhaust manifolds