Sounds like you've done some research.

Additionally, some of the 'one piece' blocks have no mechanical fuel pump provision.

Keep in mind that late '85 then '86- up have lightweight cranks and are externally balanced on the Flex/flywheel end.

Anything I/we missed we will read about shortly.

 

The oiling system is different. Uses different oil pump bolt. Some use different filter mount and by-pas system. Takes different soft plugs internally. Not all blocks are machined/drilled for roller cam. Not all blocks are machined/finished for mechanical fuel pump. Block casting around the cam in the front of the block is different from two piece blocks. SOME have extra mounting holes at the front area of the block.

 

Here's the basic breakdown and there are exceptions.

Up to 85 they were all traditional small blocks; perimeter valve cover bolts, standard intake bolt pattern, 2-piece rear mains.

In 86, most of them switched to centerbolt valve covers but the rest stayed the same.

Starting in 87 they were all 1-piece rear mains, centerbolt valve covers. Carb and TPI had standard intake bolt patterns and roller blocks, TBI intakes used a different bolt angle on the center bolts. TBI blocks are also mostly not roller blocks. Of the few TBI blocks that were roller blocks, none or few were roller cams.

Starting in 96 they were all Vortec-head, 1-piece, roller block and cam, and the intake bolt pattern was totally different. Basically, they were functionally the same block as the 87-95 roller blocks with vortec heads.

Or, to look at it this way, if you want all of the "best" features in the block, a 96 and up vortec block is the way to make sure you get it. Otherwise you can find a passenger car block from 87-95 and just check to make sure it has provisions for a roller cam. From there, heads need to be considered. They can basically be broken down into the standard sbc found on all carbed and TPI setups. TBI used its own, and Vortec used its own.

As far as accesssory bolt holes, they are all functionally the same. You can bolt a 1999 serpentine drive onto a 1957 small block. Water pumps are the same except serpentine pumps are reverse rotation and won't pump water if you run them the wrong way.

Exhausts pretty much all bolt up. The only interference you will probably encounter is head bolt interference depending on heads, bolts used, and which chassis they're in.

You might find that some blocks don't have all the bosses drilled; for instance, my marine vortec block didn't have the lower bosses drilled where an air pump would normally be installed, but as far as things like power steering, AC, and alternator, it should be possible to mix'n'match accessory drives and find holes for everything.

Bellhousing bolt patterns are all the same. 2-piece cranks have different bolt patterns than 1-piece, and there are at least two flexplate-to-converter patterns.

Keep in mind that none of this includes the 92-97 LT1 or the 98 and up LS1 engines. They're obviously different critters. The LT1 shares a lot in common with traditional small blocks but it gets hairy. The LT1 block is very similar to a 1-piece roller block, but the heads, water passages, intake pattern... all of it is different.

 

Well from what I read I knew about the fuel pump thing and did not know about the oil pump though thanks on that one. Main concern for me was heads intake and accessories. I already know what crank, rods, and pistons I am getting along with roller cam. Just need to know are the heads and intakes sold for the 283-400 small blocks bolt on two a one piece seal 350 block? O well hopefully someone has built one before and can help me out.
Thanks to all who replied.
Eric

 

Cool thanks for the info. The block I was looking at getting was gm part number NAL-10105123 , That is the block I was wanting to get brand new and get the proper stuff to bolt up to it. I was wanting to get a set of world sr heads and a edelbrock performer or weiand street warrior intake manifold for it. Just wanted to know if they would bolt up to this block ok? I know it has the setup for the roller cam and if the lifter valley does not have the spider rack holders drilled then it can be tapped I know that. Anyone know anything about this block? Thanks for the info man that helps out a lot.
Eric

 

I don't know if anyone mentioned it but there is a ball bearing underneath the rear main bearing on a one piece rear main.

 

Eric; any SBC1 head will bolt up to any SBC1 block. You can put vortec heads on a 1957 block, or put old heads on a brand new Vortec block. That includes aftermarket SBC heads and aftermarket SBC blocks. Obvious attention would need to be given to head chamber design and piston dome/dish design since the chamber shapes are different, but as far as physically bolting them on, go for it.

 

Hello Curtis thanks for the info I really appreciate it that is what I was wanting to know. I know about everything else just need to know about the heads and intakes go with what type of heads you got anyways.

Now I know what to do for my next build. Just cant decide if I want to get a gm L 31 short block for around $1200 or get other parts and have to spend a little more.
Eric

 

Do some poking around. I found a reman marine vortec longblock for $1200, no core, next day AIR drop shipped to my house. I highly recommend this guy if you want to go with him... I know he will do automotive engines, but I don't know if he is good or experienced at them. The only real difference with marine longblocks are looser clearances at the bearings and rings, along with Inconel exhaust valves. The valves won't hurt a street engine, but I wouldn't recommend a marine shortblock for the street. Anyway, call Raul at Rapid-o-marine in FL. I'm pretty sure their ebay name is rapidomarine. Good stuff, great price, great service.

At any rate, there is stuff out there for a good price. I know my local machine shop had a flat rate for remanufactured SBCs with a core charge. it was something like $860 for a shortblock and $1134 for a long block. Vortecs might be slightly more for a long block but the shortblock should cost the same. I also like the local service idea. I don't have to ship anything if it breaks under warranty.

I have at least two sets of Vortec heads that I'm not currently using. One set is used from a marine engine, and the other set is pocket ported and already modified for .550" lift. I think I'll use the marine heads to build a spare 350 for my boat, and the ported ones on a 383 i've been itching to build for an old Scout rock crawler.

Oh, and if you hear about 062 heads being better than 906 heads. The difference is in the exhaust valve seat on the 906 heads being a little intrusive. If you smooth out the seat shoulder during a valve job, the two heads are basically identical and equally up to the task. One of my engines actually has one of each casting and has no ill effects.

 

You can get brand new 2 bolt 350's for $2100 and brand new 4 bolt Vortec 350's for $2140. And thats an adevrtised price, should be able to find them cheaper.

peace
Hog

 

The only real difference with marine longblocks are looser clearances at the bearings and rings, along with Inconel exhaust valves. The valves won't hurt a street engine, but I wouldn't recommend a marine shortblock for the street. Anyway, call Raul at Rapid-o-marine in FL. I'm pretty sure their ebay name is rapidomarine.

Why dont you recommend a marine shortblock. Is it because of the larger bearing clearances?

If I was willing to live with some cold startup bearing knock, would you still advise against a marine shortblock?

GM has a TSB about incorrect main bearings being installed in Vortec 350's and cold startup knock being an issue to some owners.
I have driven my 97 Vortec 350 since 18,000kms, it has over 400.000 kms on it now, and when its cold out I have had some bearing knock on cold mornings.
I have seen some new marine Vortec 350's for very cheap and may use 1 based on your recommendation.

Also, would the Vortec heads used on the marine 350s up until around 2008 be the type that GM installed the hardened exhaust seat insert into? I have heard these hurt low lift flow, and woudlnt want to pull the heads of a new longblock to grind them down.


BTW Do you think this blueprinted shortblock is anywheres near the money of $2159? I mean I can get a complete new 4 crate engine for that.

http://www.sdparts.com/product/12556121BP/L31350SBChevroletBalancedBlueprintedShortBlock.aspx

heres a 4 bolt main shortblock for comparison.$1189
http://www.sdparts.com/product/12556121/350L314BoltMain350ShortBlockAssembly.aspx

Thanks in advance.

peace
Hog

 

Why dont you recommend a marine shortblock. Is it because of the larger bearing clearances?

Yes. There is no need for those tolerances on a street engine. A street engine on the highway is running at 2500 rpms and 10-20% throttle. A marine engine is often cruising at 4500 rpms and 80-90% throttle. Marine engines also typically use lower thermostat temps and are designed to run mostly during warmer temps. Automotive engines use higher temp stats and are designed to operate at a much wider range of target ambient temps. I have known guys running marine engines on the street with marine tolerances, but the oil pressure is all over the board depending on temperature. There are other subtle differences like ring end gap. They're wider on marine engines since they run at such high loads and don't have to pass a smog test.

The good news is that the marine cranks and mains are the same as a street engine. The differences are with the bearings. If one wanted to be adventerous they could swap the bearings. But... just use an assembly designed for the street. No reason to pay "marine" prices only to have to re-engineer the whole thing.

If I was willing to live with some cold startup bearing knock, would you still advise against a marine shortblock?

Yes, because bearing knock leads to bearing spun.

GM has a TSB about incorrect main bearings being installed in Vortec 350's and cold startup knock being an issue to some owners.
I have driven my 97 Vortec 350 since 18,000kms, it has over 400.000 kms on it now, and when its cold out I have had some bearing knock on cold mornings.

I highly doubt its bearing knock. Most SBCs produced after about 1990 use VERY short piston skirts. Until the pistons heat up, they rock in the bores and the skirts knock on the cylinder walls. Its called piston slap and its very common, but not a reliability issue. My 96 LT1 has had piston slap since 30k miles and it now has 126k miles with no worries.

Also, would the Vortec heads used on the marine 350s up until around 2008 be the type that GM installed the hardened exhaust seat insert into? I have heard these hurt low lift flow, and woudlnt want to pull the heads of a new longblock to grind them down.

The marine vortecs use the same head castings as the trucks; either 062 or 906. In my research, the 906 marine heads use the same hardened seats that the trucks do. The real-world difference is very neglegible. It costs a couple cfms at most. I have one Vortec engine running one of each head and I can't see any difference. If you want, you can "port" the shoulder of the seat and then its identical to an 062. The nice part about marine Vortec heads is that they have Inconel exhaust valves. Its not necessary, but its a nice upgrade.

As far as price, its hard to say. Do I remember you're in upstate NY? If so, you have access to a billion marine engines But I strongly suggest you build it with "street" tolerances. Use marine sources for cores, but the build should be street.

 

Thanks man, I appreciate it. I live in Woodstock Ontario Canada. And yes theres lost of marine places around here.

I wish i could find the GM TSB for you about the incorrect bearing issue in the Vortec 350 trucks. it seems as though the problem affected trucks that were equipped with oil coolers, morso than others. If it was bad GM was installing replacement main bearings, in vehicle, under warranty.

I also have heard of piston slap, but the noise goes away quite quickly. Not saying your wrong. It just fit the beaing noise TSB moreso than piston slap.

Thanks for the info, I have always wondered about those marine engines. I am running a marine intake on my truck using 24 pph injectors along with the stainless fuel rails, and stainless tipped marine Multec 2 EV6 injectors. No more poppets for me.
This intake
http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/marine/2009_5700_Marine.pdf

Here is the conversion for the 96-99 L30/L31 trucks.
http://www.pacificp.com/forum/viewtopic.php?t=317

Have a great day.

peace
Hog

 

You are wise, grasshopper Those marine intakes take care of the shortcomings of the truck intake.

I did the opposite and it bit me in the butt... I had a truck Vortec intake sitting around so I put it on my marine 350. One of the hoses in the spider cracked and hydrolocked the #7 cylinder. Never again.