The elusive 224/3.7 MerCruiser banger

Sounds like a good plan! I think you can get there. Vintage Boss 429 stack injectors are really rare. I have never been able to find one let alone figure out how to pay for it! Mine is a Arais hemi BBC unit which seems to be rare too. 426 hemi have been used too. Kinsler made big units for wedge heads that maybe could be adapted to your head.

 

I contacted Kinsler earlier this year. I asked if they would do half of a Boss setup for me. This guy that emailed me back had no idea what I was talking about, and said they don't make Boss 429 injection. So, I sent him this link on their website:

https://kinsler.com/Shop/product/kinsler-bb-ar-hemi-call-for-pricing/

He said they don't make anything like that. Whatever...

 

There's a guy that used to run one of those in Comp Eliminator in a rear engine dragster. It made 470 HP@7500 RPM and ran mid 8's in the quarter with a C460 head.

 

Yep, that was Chris and "Sarge" Nicholas in Arkansas. Sarge passed away, and Chris has parted everything out. I am not sure if anything has sold yet. There are a few magazine articles on the web about it.

 

I talked with them to buy parts for my set up, again they said it would never work! 3 inch throttle is to big for 242 inch engine. They would not sell me anything. I know they don't make anything for a Boss head but they did do a 3.250 throttle bore for someone with a wedge head. I think it is the guy that runs the Facebook page on these engines. Its just a mounting angle and bolt angle but may be made to work On a Boss head.
Hilborn is the only Boss 429 intake I am a where of, and that looks like your picture. What I can tell there were only 13 of them and they were for the 494 CanAm engines

 

When Holley bought Hilborn, all inventory was sold off and it sounds like historical records disappeared. A friend in Omaha, Nebraska bought most of the casings. He is slowly working through that stuff and making complete units to sell. I already tried to buy some raw castings to modify. Most likely he will be doing my head and intake work. Boss Fuel Injection and Smithberg Racing are his business names.

 

I can make some patterns for castings if you need some. I made patterns for side draft Weber intakes for the Chevy 6 250/292 and the 153 4 cylinder and a front mount throttle body EFI for the Chevy 6 250/292. Been thinking about making something for the 3.7 for a while....

 

I would be interested in a sidedraft Weber Boss intake for a street motor at some point.

 

Can you provide any dimensions like port spacing and shape/size, bolt pattern...etc...?

 

I will PM you later today.

 

@dennis g,
Referring back to your post #1028:
To adapt the Vega vacuum advance to a Mercruiser distributor, it appears that you only need the vacuum advance plate and the vacuum can itself. Is this correct?
Also assume that you would use the points etc. from the Vega, or are they the same?

Thanx,

Bruce

 

That vacuum distributor was common.
I found a 1969 Rambler vacuum advance distributor that was close as a good parts source. The 50 year old vacuum pot was worthless but there were some new ones on ebay that looked right, were a perfect fit and worked well. The points are the same. I remember having to drill mounting holes for the vacuum can. The two bodies were otherwise the same including the hole for the advance lever which was a long curved thing (2 or 3" long). The Merc distributor shaft has to be used as its length and gear are specific to the 3.7. You will have little trouble making it work as the parts interchange with minor adjustments.

It was a very good change.

A boat engine designed to run full throttle on high octane fuel is not happy at half that speed in a car on 87 octane fuel. Changing the cam licked knocking but it still ran hot, (usually 230 but sometimes 260 degrees). Low compression(8:1) "bathtub" pistons and vacuum advance allowed 42 degrees total advance maximum and solved the overheating . It now runs at 180 degrees. The low compression vacuum advance engine has noticeably more power on the road at speeds I usually run it (around 2200 rpm with a 3.07 rear end).

 

John Deere head bolts plus spacers.

 

I'm thinking of buying one of the C3 dampers this guy has for sale since they're cheaper than any new aftermarket dampers but I'm not 100% sure it will work. Has anyone actually put an SBF damper on one of these engines. Lots of talk over the last 100 pages but no pics...




I've never used a fancypants aftermarket race damper on anything but it seems like those are my only option for an internally balanced SBF damper. Do these dampers use some sort of common crank pulley?

 

Of the pair of "cheapest stainless shorty headers money can buy" that I bought the driver's side (as installed on a typical V8) has comical amount of interference with the solenoid. This would probably be a non-issue on a PMGR starter and definitely a non-issue on a clockable one but I don't really want to constrain myself to using those.





It's sitting on the solenoid in those pictures.

If anyone running a small starter thinks they can use this it's yours for little more than the cost of shipping.

 

I was going to use a aluminum innovators west small block damper, but read I should keep the weight, so I had a old nos motorsports neutral balance 351w damper so I went with that. I had a 69 FE lower pulley that would of worked but I ended up making a new lower pulley. Any small block damper you use will have to be neutral balanced.

 

The pass side header fit just fine though. The starter goes in like a hotdog down a hallway. From the crank center-line to the edge of the collector flange is 14" or thereabouts which is a consideration...

 

I made my header for mine. Collector cost the most to make it. This is the best I have of my damper that I have.

 

Found a earlier pic of the damper I used.

 

I’m curious why you didn’t you use studs instead of head bolts. I order them by length for my GMC 6 stock heads and aluminum 12 ports. I just feel more comfortable tightening using fine threads for the nuts which are 12 point and shouldered.

 

I just don't think that the head fasteners themselves are anywhere near being a weak point that needs addressing on these engines. If I could have gotten proper thread engagement with the stock bolts I would have reused them.

How much do custom length studs cost you if you don't mind me asking? I assume your GMC is 1/2 or 7/16.

I really like your alternator mount location. I'm planning on something similar myself.

 

I made four or five alternator mounts, kept moving it up or out to try to clear the lower rad hose as I kept moving the water pump to clear the fuel pump. Its a simple flat plate and a bent upper strap.

 

Has anyone come across an off the shelf motor mount that works? I have a pair of Chevy V8 mounts I can make work but if there's a parts store solution I'd prefer that.

 

chevy v6 mounts are what I use because the v6 is closer to the 3.7 in weight and they are available everywhere. Motor mounts are tuned frequency devices so engine weight and rpm may matter. Aftermarket mounts for chevy v8 can be crude things that I'd not use because of poor design, excessive hardness in the rubber and shoddy construction in India. I have photos years earlier in these posts. Some use the little round Ford mounts from the 1930's.

 

If you run EFI Webers you could use a 460 IDA intake and the throttle bodies would be at 45*. For Boss head, here is a fabricated intake and port spacing looks close enough to Webers that all you need are a couple plates and some angled round tubes from https://parts.sharpeproducts.com/pipe-tube-elbows.
https://bangshift.com/bangshift1320/four-weber-boss-429-intake-manifold/

 

Kaase has a Weber intake for the Boss. That is most likely the route I will be taking.

https://jonkaaseracingengines.com/shop/boss-nine-parts/boss-nine-stack-injection-intake-manifold/

 

Hey crew. Just spent a few weeks reading all 106 pages. Been to this thread a few times in the past decade, however now that my next project is starting to come to fruition, thought I would finish reading and post since I am looking at using a Mercruiser 470 derivative in my 1933 Ford pickemup truck

these motors were prop rated and working backwards on the MC/MR/R/Alpha drive, thats 20 hp more at the flywheel making these 190 - 210hp with the smog era iron head

Been playing with boats and cars for over 40 years

The goal is to use one of the two 470's that I am picking up with the following changes:

• PCE head (because aluminum block needs an aluminum head)
• bore spider (or deck plate or what ever we want to call it. same concept used decades ago in boosted porsche 928's by my bud Murph and used by the honda guys). it will simply be set in place to keep the bores from moving. no need to weld it
  
• water cooled voltage regulator changed for air cooled unit from industrial Kawasaki motors and reverting back to the stator charging system as I will only have the lights and charging for a load
  
• vac advance modified dizzy

this will give me about 220hp and plenty of torque for my daily driver

carb will be stock rochester or an edelbrock AVS initially because I have access to it, then will either be webbers or a a blower and a holley 650

The two motors I am getting both have had the speedi sleeve fix for the waterpump done almost 30 years ago. Both were swapped to alternators because the stock water cooled voltage regulator eats itself if the coolant temp gets to 180 (only 10 degrees above their 170 degree standard operating temp). Additionally, the head gasket will go south with the iron head if the temp gets above 190.

I find it odd that not one mention of using the speedi sleaves for the cam snout to fix the issue of the seals for the water pump was ever used. one thread on hard chrome plating, and many threads on adapting a toyota pump or using electric pumps

however if speedi sleeves can last 35 years and 100 hours a year on these motors, they will work in an automotive application.

Regarding the trans.... not cutting the block. made too many custom clutch installations over the years to need to do that. may go with the T5 with dual clutch disks or may go with the Aisin AR5 I have with a LS swapped bellhousing and custom clutch assembly

I may reach out to a few of you on the deck plate CAD, etc.

 

I did it. One sleeve where each seal rides. Haven't ran the motor yet.

If I were ordering a custom cam I'd have that snout turned 1/4 undersize and I'd press some ~1/8 wall stainless tube over it.

 

Probably press a 16 gauge wall tube over an 1/8" undersized snout. However the speedi sleeves are usually 410 stainless and sufficient