What makes a marine engine a MARINE engine

[ckgreenman]

Re: What makes a marine engine a MARINE engine

This cam would get you close...it's for an 87 or older sbc.
LINK

Of course without knowing the many other parameters like CR, head design, etc it's tough to say.

That cam actually is not far off from my original one although mine is a roller.

Here's the one I've been looking at:

http://cranecams.com/?show=browsePa...-350 C.I.&partNumber=109811&partType=camshaft

 

[270win]

Re: What makes a marine engine a MARINE engine

That cam actually is not far off from my original one although mine is a roller.

Here's the one I've been looking at:

http://cranecams.com/?show=browsePa...-350 C.I.&partNumber=109811&partType=camshaft

Yeah, and I prefer a HR over a FT cam...actually, I won't build a flat tappet engine anymore. The cost difference is well worth the added durability and efficiency.

That cam is a little hotter than stock, but very close. It's just hard to recommend a cam without knowing everything else.

We're building a 461" stroker motor for my 68 GTO right now. The bottom end is done, but we're waiting on the head flow numbers and the intake numbers to decide on the HR cam. I say that to say how hard it is to recommend a cam out of thin air.

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

I will save those types of questions for when I settle on an engine I reckon. The main reason I asked about the RV cam is because I've seen several engines advertised that are already equipped with an RV cam. The specifics on those cams are not given in their listings.

 

[ckgreenman]

Re: What makes a marine engine a MARINE engine

Yeah, and I prefer a HR over a FT cam...actually, I won't build a flat tappet engine anymore. The cost difference is well worth the added durability and efficiency.

That cam is a little hotter than stock, but very close. It's just hard to recommend a cam without knowing everything else.

We're building a 461" stroker motor for my 68 GTO right now. The bottom end is done, but we're waiting on the head flow numbers and the intake numbers to decide on the HR cam. I say that to say how hard it is to recommend a cam out of thin air.

I picked that one because of how close it was to stock. Yeah it's a little hotter but then I kinda want a little extra. I guess I probably should stick with the stock cam but it's twice the price (almost $500). I might see if I can match the stock one by getting a custom grind locally. It should save me a couple hundred.

 

[270win]

Re: What makes a marine engine a MARINE engine

I will save those types of questions for when I settle on an engine I reckon. The main reason I asked about the RV cam is because I've seen several engines advertised that are already equipped with an RV cam. The specifics on those cams are not given in their listings.

I'm sure they just mean a towing cam or something slightly over stock for pulling applications.

In hot rod motors you used to hear alot of people call a cam that was pretty hot, but not a full race cam a 3/4 cam. I think Comp...or maybe it was Crane used to advertise a 3/4 cam. Now people want to know exactly what the cam does, the technology has come a long way.

 

[270win]

Re: What makes a marine engine a MARINE engine

I picked that one because of how close it was to stock. Yeah it's a little hotter but then I kinda want a little extra. I guess I probably should stick with the stock cam but it's twice the price (almost $500). I might see if I can match the stock one by getting a custom grind locally. It should save me a couple hundred.

I'm sure we'll do a custom grind on the GTO cam.

I'm getting a motor from Rapido and letting them deal with the particulars...just gonna set it up with all the tin and accessories and drop er' in.

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

I was thinkin about an edelbrock carb. Reckon I need a 600cfm, 650cfm, or bigger to feed a 350.

 

[270win]

Re: What makes a marine engine a MARINE engine

I was thinkin about an edelbrock carb. Reckon I need a 600cfm, 650cfm, or bigger to feed a 350.

What's wrong with your current Q-Jet? Honestly, IMHO, the Q-Jet is superior to the Edelbrock. The Edelbrock is based on the old AFB carbs that went out in the late 60's. The Q-Jet was the new standard...

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

I have no problem with the q-jet. In fact, I'd prefer not to have to buy a new one. I just figured the edelbrock was better. I had a q-jet on my old '84chevy truck and it was a piece of junk so I put on an edelbrock 650. The q-jet throttle response was terrible, but that was on a 305. I'll just stick with that for now, and change it if I don't like the performance.

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

I've also heard that q-jets are a pain to repair, and that they're never the same after a rebuild. But I've never tried it.

 

[270win]

Re: What makes a marine engine a MARINE engine

I have no problem with the q-jet. In fact, I'd prefer not to have to buy a new one. I just figured the edelbrock was better. I had a q-jet on my old '84chevy truck and it was a piece of junk so I put on an edelbrock 650. The q-jet throttle response was terrible, but that was on a 305. I'll just stick with that for now, and change it if I don't like the performance.

I understand, and the QJ gets a bad reputation because of people who don't know how to tune and set them up. I'm no guru with the Rochesters, but someone like Alpheus could be of big help to you in setting yours up. I'll say this, the QJ is superior to the Holley and Edelbrock carbs in it's ability to deliver excellent idle, response AND much better economy in fuel use. And if yours is set up right, it'll out perform the others.

Ask around the local speed shops for someone that is good with the QJ. If you don't have any luck with that, I can refer you to a friend of mine named Cliff Ruggles. Google his name and you can learn about the QJ carbs.

He's building one for the GTO right now....and I have Holleys, QFT and Edelbrock carbs on hand at the shop.

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

Sounds good. I'll definately take some time to educate myself of the q-jet in the mean time. Honestly, when I was 16 and got my chevy, I just wanted an edelbrock because it looked way cooler than that ugly ol' rochester.

 

[270win]

Re: What makes a marine engine a MARINE engine

Sounds good. I'll definately take some time to educate myself of the q-jet in the mean time. Honestly, when I was 16 and got my chevy, I just wanted an edelbrock because it looked way cooler than that ugly ol' rochester.

Yeah, they aren't exactly pretty...

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

I will be better off with a different intake manifold though won't I? Edelbrock performer maybe.

 

[270win]

Re: What makes a marine engine a MARINE engine

I will be better off with a different intake manifold though won't I? Edelbrock performer maybe.

If you do a cam swap I think the performer RPM will help...you want a dual plane for sure. And if you run the Qjet remember to get a spread bore intake.

A cam, head (vortec) and intake swap would give you a big improvement...especially over the 305.

 

[ckgreenman]

Re: What makes a marine engine a MARINE engine

Gimme a Q-Jet any day. I loved the Q-Jet on my Camaro back in the day. and to be honest there a helluva lot easier to work on than a Holley in my opinion. I don't have any experience with the Edelbrock/Weber/Carter AFB style carbs other than my current one which is in pieces awaiting a really good cleaning and a rebuild kit.

A friend of mine is giving me an Edelbrock 1406 which will probably need a mod to make it marine legal (fuel pump vent fitting) that I'll probably use instead.

 

[ckgreenman]

Re: What makes a marine engine a MARINE engine

Here's another question that I don't think has been covered (or did I miss it).

What about valves? The local mechanic I've talked to said that marine engines came stock with Inconel valves ($40 a piece) on the exhaust and 100% stainless on the intakes. Reading the Mercruiser manual it just says "heavy duty" valves but doesn't specify the material.

 

[270win]

Re: What makes a marine engine a MARINE engine

I really don't know right off hand. I was thinking stainless for both...maybe someone else has a better idea of what they came with from the factory. "Heavy Duty" can mean lots of things...

 

[270win]

Re: What makes a marine engine a MARINE engine

Gimme a Q-Jet any day. I loved the Q-Jet on my Camaro back in the day. and to be honest there a helluva lot easier to work on than a Holley in my opinion. I don't have any experience with the Edelbrock/Weber/Carter AFB style carbs other than my current one which is in pieces awaiting a really good cleaning and a rebuild kit.

A friend of mine is giving me an Edelbrock 1406 which will probably need a mod to make it marine legal (fuel pump vent fitting) that I'll probably use instead.

I'm the opposite, I can do a Holley with my eyes closed...I'm learning about the Qjets now, but know just enough to be dangerous...

 

[BigBoatinOkie]

Re: What makes a marine engine a MARINE engine

If you do a cam swap I think the performer RPM will help...

Isn't the performer RPM intended to yield the most power from 1500-5500 rpm, where the performer is for 0 rpm on up? Seems like the performer would be better for a boat if what I stated is true. Well maybe not 0, but lower rpm.