Experts, please advise, old or relatively recent blocks are preferable?

[DeepBlue2010]

I am building a 350 out of a cracked 305. Found a candidate block with casting number 3970010.
References say it is 69-79 block. Seller says it has 10% more nickel which makes it high performance candidate, I searched all over for definitive opinion in this but it seems to be one of these ?things? that everyone has his/her own opinion about.
In any rate, I am not planning to build any performance monster or anything. The max rated HP for this block is 370 and I am planning to use components to support that.
My question is, is this a good block candidate given that it is 69-79 casting or should I continue looking for a more recent one? It is still standard bore wasn?t rebuilt before.

 

[alldodge]

I would pay no attention the composition of the block, for me that's meaningless. Your block can be either 2 or 4 bolt mains. Look for one piece rear main seal and roller cam and 4 bolt main, would be tops on my list.

I would keep looking

 

[DeepBlue2010]

AllDodge,

Thanks for you reply. This roller can specifically puzzles me a little. I actually asked the question in a separate thread only a day or two ago. Is roller cam a characteristic of the block or not? In other words, can a roller cam installed on any block provided that you do the due diligents when it comes to the heads. In other words, recalculate rocker arms length, spring tensions based on the cam lefts, etc.

Or if the block was originally a flat tappet, it MUST stay that way? Bondo answered the questions that the roller cam can replace a flat tappet, do you agree?!

The block is two pieces main seal, is this doomed to leak even with good seal and installation techniques? Is it a deal breaker?

 

[Bondo]

Ayuh,.... A late model block gets ya the 1 pc seal, 'n roller cam,.... mid-90s, 'n newer,....

 

[alldodge]

Bondo is correct in saying you can install a roller in a flat tappet, but it is much easier and the high performance pieces which keep the lifters from rotating are better in the newer blocks, otherwise your tying a lever between two lifters to keep them in position. More things to go wrong at 5000 rpm

Its all good and will work (old or new), but for very few dollars more you can get something which can work out much easier and the one piece seal is the way to go.

As always just my opinion and would be what I would do

 

[DeepBlue2010]

Makes sense, thanks to both of you. Your guys input - as always - is much appreciated.

 

[NHGuy]

Also if you already have the one piece or 2 piece style coupler you may want to stay with that to avoid further cost.

 

[DeepBlue2010]

Good point. That is why is was asking if the two piece is doomed to fail regardless; In such case, I would go for 1 piece no matter the extra cost.


Is two piece a failure waiting to happen no matter what?

 

[alldodge]

Is two piece a failure waiting to happen no matter what?

There will always be cases where the 2 piece will not leak, none of them were real bad, just a few drips most the time, some worst then others. The 2 piece design makes it hard to seal the corners where the pan meets the block and around the crank. The one piece seal just doesn't leak in most all cases due to a better design

 

[flipbro]

One piece is nice. As stated you will need a flywheel and coupler. Also cheak the block to make sure the hole for the macanicl fuel pump is there also stock roller cams do not have the lobe to run a mecanical pump. I changed my 1984 5.7 to a 95 1 piece and am happy. But was a bit of extra expence. Also roller cams only come in the truck blocks. Car bocks didn't but did have the holes in the valley and under the timing gear too run one.

 

[flipbro]

By the way I've run that casting in my vette and z28 great motors and no rear main leaks.. I also run one for 2 years in a boat and no leaks. And if you boat in salt water the higher nickel may be a good thing..

 

[Scott Danforth]

I agree on the one-piece seal and roller can. I personally would look for a mid to late 90's truck motor with a manual trans and get the vortec heads and flywheel too

Build it with a stroke crank

Looking at 1 ton and larger trucks will bet you 4-bolt mains. Since this is a rehabed motor, throw a heat exchanger on it if your boating in salt

 

[DeepBlue2010]

Good advice all, thanks a lot. I am building this 350 as a backup for my current 4.3LX vortec that powers a 22 foot Bayliner. I am building the Bayliner to be a fishing machine. I would like to take her to the coast of WA - not the Puget Sound - and go 15-20 miles deep in the Pacific for tuna fishing. She needs to be able to stand to some rough seas and cut easily into some waves.

My build plans for the vessel will make her heavier than it was originally; added layers of 1708 to strengthen the hull, Stronger bulkheads and more of them, wider stringers and beefy transom. I am worried that after I am done, she will be underpowered by the 4.3 but I am not sure. I guess I will never be without actually trying the 4.3 and see it in action.

About the stroker, I?ve been contemplating the idea for some time now but I have one problem with it. I have an Alpha one outdrive on that boat; she will take the power out of 350 just fine; Alpha one behind a 350 is not uncommon for a power train. I will need to change gear ratios of course.
What I am not sure of is if it is a good idea to have a 383 with that Alpha. I am also trying ? as hard as my wife would like me ? to not allow myself to go as far as trashing the whole setup and go for a Bravo but I am not ruling the option out, just want to make sure if I go that route, I have a damn good reason to.

So, what do you guys think

Alpha + 4.3
Alpha + 350
Alpha + 383 ??
Bravo + 383

By the way, what is the average extra gas consumption rate for 383 over 350 if anyone has experience comparing the two?

 

[alldodge]

Buddy has a Checkmate, 383, and alpha with a 8 inch extension box and it does fine. The Checkmate weights much less then your Bayliner so that will also play into the equation. Adding extra weight with glass and everything else adds to the problem. In short your going to be pushing it with the 383 IMO.

As for gas, more power more gas, if your on the edge with funds don't do it. Also if you go with a Bravo, there is again more weight

 

[flipbro]

For what you are doing I would stick with just a 350 with a nice cam aluminum dual plane intake and a set of 906 vortex heads. Very easy to toon and reliable power. Just my opinion..