Boat engine parts vs. Car engine parts?

[Dr. Radio]

In an attempt to locate new old stock parts "just in case" for my Chevy's 307 v-8, I have run across listings for marine motor applications.

Can you use "marine" parts in a car engine? I'm assuming that some of the vintage speed boats literally used GM/FORD etc engines in them?

For example, while searching for a factory camshaft, I ran across this listing. Would this potentially work as a stock replacement?

https://www.ebay.com/itm/323934498463?m ... media=COPY


I will NOT buy modern new parts. There have been too many reported instances that the "big names" in engine rebuilding parts suppliers get their parts from overseas and the parts are not manufactured correctly and can and have destroyed engines.

[William]

I do know that having spent 40 years in the car business that engines that were in vehicles were also used in boats. Things were changed for cooling the engine, exhaust, and keeping the electrical systems water proofed. Also oil pans could be larger for more oil capacity and cams maybe different to offer more power. Maybe someone else on the forum can shed more light on the subject.

Bill

[danrclem]

I think some boat engines ran in a reverse rotation when compared to a car. If nobody else here knows for sure whether or not that cam will work maybe you could check a boat forum or a Chevy forum to find out for sure.

[TC Chris]

2nd try. Many marine engines are auto engine conversions. They had certain modifications like water-cooled exhaust manifolds, crankcase vents running to the carb intake, and "ignition-protected" electrical accessories like starters and generators. Those are completely enclosed, unlike the open-case ones in cars, the prevent sparks from igniting gas vapors in an enclosed space (boom!).

Going the other way, if you know your cam specs you could probably figure out if the Chris-Craft version would work. The question is whether boat engines had different torque curves to match a boats needs. Boat are usually direct drive in forward with no multi-speed transmission as in a car. The cams may have been optimized for different torque curves in the boat. The old-boat groups could probably give some advice about camshaft interchangeability.

Chris Campbell

[walyfd]

I know I've heard a lot of chrysler 440 and cadillac 472 and 500s were modified for boats so there's gotta be some process or kit. A block is a block.

[danrclem]

I found this and it looks like the cam was used in car engines for several years in the 60s and 70s but I would still look elsewhere to make sure it will work. It looks like it was used for a wide variety of engines from mild and up to 300 hp.

Camshafts have supposedly come a long way since then so there may be a newer grind that would work better for you. There have been a lot of flat tappet camshafts wiped out during break-in. Some say it's the camshaft material and some say it's because the lack of zinc in the oil. Very well could be both. New camshafts work but the break in needs to be done by the book. You'll also need new lifters for a new flat tappet camshaft.

"Indestructableforce - 6930 is the last four digits of the cam's casting number, 3896930, which also has a horizontal diamond for the casting symbol. The Chevy part number for that cam is 3896929.

In 1967, it was the cam for the 283/195hp; 327/210hp, 275hp, 300hp; and 350/295hp.

The specs on that cam are: (read int lift, ehx lift, int duration, exh duration, rocker ratio) .390 .410 310 320 1.50

In 1968, it was the cam for the 307/200hp; 327/210hp, 250hp, 275hp, 300hp; and 350/295hp.

In 1969, it was the cam for the 307/200hp; 327/210hp, 235hp; and 350/250hp, 255hp, 300hp.

In 1970, it was the cam for the 307/200hp; 350/250hp, 300hp; and 400/265hp.

In 1971, it was the cam for the 307/200hp; 350/245hp, 270hp; and 400/255hp.

In 1972, it was the cam for the 307/130hp; and an optional cam for the 350/165hp, 175hp, 200hp; and 400/170hp.

In 1973, it was the cam for the 307/115hp; 350/145hp, 175hp, 190hp; and 400/150hp.

In 1974, it was the cam for the 350/145hp, 185hp, 195hp; and 400/150hp, 180hp.

In 1975, it was the cam for the 350/145hp, 155hp, 165hp; and 400/175hp. All of these applications had the same specs as the initial 1967 application."

[danrclem]

I started a discussion on Hotrodders.com about this cam and so far the consensus is that it will work. It's a very good site with a lot of helpful people if you're interested in joining. If you want to follow I left the link below.

https://www.hotrodders.com/threads/will ... st-4872936

[William]

Thanks, Danny, you did a lot of work to help out the Doc and I hope it works out for him.

Bill

[danrclem]

Glad I could help Bill. I know Scott Danforth, one of the people that replied knows a lot about boats.

[Dr. Radio]

Dan,

Thank you so much!

I really appreciate the info. I did purchase the camshaft in question from eBay. Fingers crossed that it arrives in one piece and isn't misrepresented.

Here's a little more background....

I'm trying to collect N.O.S. parts for engine work as the 307 is on borrowed time, I'm sure. I'm no engine guy--but I do know that modern and reproduction parts are garbage. That's why I thought I would ask here, even though I am a member of some automotive boards, I don't need to read through 14 replies of "just junk the worthless 307 and drop in a 350 crate motor," or "Do an LS conversion, then you don't have to worry about obsolete parts." You get the idea.

The biggest issue I'm dealing with, is, I know the parts are out there, but they are not all wrapped up in a shiney GM bow with original part numbers. There are a lot of other "vintage name brands" that provided this stuff off the shelf, but I have no old reference books to go by.

I'm also looking for hydraulic tappets and I run into "Sealed Power" brand stuff. But I have no idea if Sealed Power part # apple-banana 123 crosses over to GM XXXXXXX.

Same thing.

This is for my 1970 Malibu. My Dad ordered this car new from the dealership. It has been in the family since new. It has under 94,000 miles on it. I've been doing restoration work (with major stuff farmed out) for 25+ years....on and off thanks to some personal stuff to deal with in between.

I'm not going to wreck a numbers matching engine with a Chinese made camshaft ordered from JEGS that wasn't conditioned properly at the factory. I hope that makes sense.

And--if you are wondering, NO, I'm not just buying parts to shot-gun one at a time to "cure" issues. I understand you need a full rebuild, new cam = new lifters, etc.

Again, Thank you and Thank you to everyone else who replied.

Joe

[William]

I think we all get it, and all prefer to do things in the same manner that you are planning. By the way, Joe, nice looking Malibu and for it to be a family heirloom is even better.

Bill

[electra225]

Sealed Power is an old brand of genuine quality engine parts. I like using lifters for Buick made by Johnson Controls. I really think that if you use a vendor of known reputation, such as Impala Bob's or similar, you will get parts of modern manufacture that are perfectly satisfactory for your 307. I applaud you for wanting to save the 307. Most folks would drop in an LS and move on. I personally think that is cheating, chicken do-do type sniveling BS. My thinking is if you want an LS powerplant, but a vehicle that has one from the factory. If you want an old car, put up with it's old car ways. I even cringe at radial tires and halogen headlamps. I used Sealed Power parts for my Buicks. Packard parts were trickier. I think your statement that ALL modern replacement parts are junk may be a bit too general. If you use a vendor of known reputation, you have an extra lever in case you have an issue. I wouldn't buy parts from a "big box" parts store. You need to find a specialty supplier who will stand behind their wares. Then find a machine shop with similar business practices. Auto restoration is not for the faint of heart.....

[Dr. Radio]

I think we all get it, and all prefer to do things in the same manner that you are planning. By the way, Joe, nice looking Malibu and for it to be a family heirloom is even better.

Bill

Thank you Bill.

[Dr. Radio]

Sealed Power is an old brand of genuine quality engine parts. I like using lifters for Buick made by Johnson Controls. I really think that if you use a vendor of known reputation, such as Impala Bob's or similar, you will get parts of modern manufacture that are perfectly satisfactory for your 307. I applaud you for wanting to save the 307. Most folks would drop in an LS and move on. I personally think that is cheating, chicken do-do type sniveling BS. My thinking is if you want an LS powerplant, but a vehicle that has one from the factory. If you want an old car, put up with it's old car ways. I even cringe at radial tires and halogen headlamps. I used Sealed Power parts for my Buicks. Packard parts were trickier. I think your statement that ALL modern replacement parts are junk may be a bit too general. If you use a vendor of known reputation, you have an extra lever in case you have an issue. I wouldn't buy parts from a "big box" parts store. You need to find a specialty supplier who will stand behind their wares. Then find a machine shop with similar business practices. Auto restoration is not for the faint of heart.....

Greg,

I'm afraid even the most top-notch sellers still can only buy from the "pool" of suppliers that rely on overseas manufacturing. I've read and viewed a lot about how the old school stuff is not really "supported", thus quality standards have fallen thru the floor, and that's kind of what you would expect with overseas manufacturing complicated by material shortages and corporate greed.

This video is from 2 years ago. I think you should watch it. This guy is no "hack" and this isn't his first rodeo. There are a number of other videos addressing this issues, but I think he did a very factual, real review.

https://youtu.be/ZJCWzVjhags?si=Rg4O_e-jK9GnpsTs

[Dr. Radio]

I started a discussion on Hotrodders.com about this cam and so far the consensus is that it will work. It's a very good site with a lot of helpful people if you're interested in joining. If you want to follow I left the link below.

https://www.hotrodders.com/threads/will ... st-4872936

Thank you again for the work.

[electra225]

The problem with using NOS parts is really two-fold. One, they are the same age as what is in the engine already. Plus, there has been advances in materials that are superior to what is original. I've rebuilt several old car engines. Buick and Packard straight 8, Buick, Cadillac and Packard V-8. Pontiac and Olds V-8. A couple 327 and 283 Chevy's. Outside of machining and assembly issues, I never had an issue. I put NOS bearings in the differential on my Buick. They went bad in less than a thousand miles and it cost me $3400 to have the work redone. Custom bearings had to be built for it. NOS or aftermarket parts for an early Buick Positraction axle do not exist. I would convert the old poured babbitt bearings to use insert bearings. Oil pumps can be souped up to provide a higher volume of oil. Synthetic lubricants are so vastly superior to what those old engines were designed to run on, their lifetimes are vastly enhanced. Time has passed since I was in the restoration business, and many of the suppliers I used no longer exist, I suppose. I find it difficult to fathom that any supplier would sell known inferior parts. I wish you well with whatever route you take.

[danrclem]

I don't blame you for not wanting to use an LS engine. I'm sure they're a good engine but I don't think they look good in an older vehicle. I really don't think they look good in a newer vehicle. I just don't like the plastic look of them.

Your car looks good and should give you much enjoyment when you get it finished.