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Roller cam 5.7L build

kennyw

kennyw

@squarebody.chop.shop on IG
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I disassembled the free boat motor last night. The block is cracked in 3 places from not being drained over the winter but with 300 hours on it, the is not much wear.

I was hoping for vortec heads, but it isn't. Any idea if these heads are better than what would be stock on a late 70s 350?

My first thought was find a new replacement block until I saw the $1200 price tags... next option is buy a used block, bore. 030 over and get new pistons. I've seen short blocks in the $100-200 range. Adding machining and new pistons to that, can I stay under $500?

Next question is the rear main seal housing, is this a typical one piece rear main or something special for a boat?

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Found this info on the heads, looks like a better head than a late 70s truck 350.

14096217 Iron heads, are centerbolt. They are 1987+ (and later) and feature 72 degree center bolts. Valves are 1.94 and 1.5 with 64cc combustion chambers. The head is the same as L98 Iron head 14011083 which is why these heads were found on this car. They came from GM parts, if not a complete crate engine. The engine part number is 12353641. This 350 crate engine came with 285 hp, although I have seen them listed as making 300 hp though thats unlikely unless there was an option.

These heads were also used on Marine 350 engines, including TBI marine engines. Power ratings were up to 320 HP depending on application. GM DID make a 300 HP crate engine with the "217" heads on it. The same engine now comes with "062" vortec heads and makes an extra 30 HP. The 330 HP 350 HO replaced the now discontinued 300 HP 350 HO
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damn, that's a shame...It's amazing the amount of power ice has... I work in Refrigeration, and have seen ice do some incredible things... crush pipes, lift concrete slabs/floors in walk-in freezers, lift frozen food cases in grocery stores 8 inches off of the floor, freeze solid inside of suction line p-traps stopping the flow of refrigerant. Crush the tubes and fins of evaporator coils, loosen and back off flare nuts on expansion valves. Split flare nuts..
It has the power to crush,crack and bend steel like it's plastic..that cast iron never had a chance...
 
Update on this:

Found a standard bore block without mains and purchased it. Dropped it off at a machine shop and they hot tanked, mag tested good, and line bored it with the caps from the other block. It is now inline to go for inspection to see if I need to bore the cylinders.

Now I get to decide how to build it... I think I want to aim for a 300-320 HP fuel injected motor for the short bed. The marine crank is supposed to be one of the stronger ones of the era and should be good for that. Probably the rods too, but that would be the limit they are good for from what I understand.
 
kennyw said:
Update on this:

Found a standard bore block without mains and purchased it. Dropped it off at a machine shop and they hot tanked, mag tested good, and line bored it with the caps from the other block. It is now inline to go for inspection to see if I need to bore the cylinders.

Now I get to decide how to build it... I think I want to aim for a 300-320 HP fuel injected motor for the short bed. The marine crank is supposed to be one of the stronger ones of the era and should be good for that. Probably the rods too, but that would be the limit they are good for from what I understand.
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Curious what’s different on the rods

Any cam specs? Usually those are really specific power band, may or may not be a good truck cam. I’d suspect all the other parts are reusable?
 
Bent77 said:
Curious what’s different on the rods

Any cam specs? Usually those are really specific power band, may or may not be a good truck cam. I’d suspect all the other parts are reusable?
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The machinist I was talking to about the block was mentioning the stock rods I have would not be good for high horsepower applications but they should be good for the 300-320 HP goal I have. They are just the typical small block connecting rod.

I do not have the cam specs but plan on replacing the marine cam with one for a truck application anyway. Yes, just about everything except the cracked block and cam should be reuseable. I am hoping I don't need to bore the new block and can reuse the pistons, but that is not the end of the world or expensive if not.
 
Definitely better news than a cracked block
 
Port match the upper intake, runners, and lower manifold. The hardware is the same for the 305 and 350. It needs all the breathing help it can get. I have a BBK throttle body, SLP runners for the project I started in 94. A stock tpi unit runs out of air around 4500rpm. The plenum becomes saturated, it can only flow so much air.
 
Darin Dochterman has some good vids on yt on porting tpi stuff. Ain't much to listen to, but good info none the less.
 
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Found one cracked head from the boat donor... so looking at options for heads. I can track down another good used matching head (cost of head plus $450ish if it needs a rebuild), see if the 305 TPI heads are ok, cast iron Vortecs ($840 ready to go) or aluminum Speedmaster heads ($550 plus parts and assembly)?

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Found one more option on Ebay for a pair of rebuilt Vortec heads at $435. The price is good but I'm thinking these heads won't work with the TPI intake...

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Yes I think the intake pattern is different


On the TPI, have someone lined up for the retune?
 
Bent77 said:
Yes I think the intake pattern is different


On the TPI, have someone lined up for the retune?
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I found an aftermarket intake that will work though! The money saved on heads will just be spent in the intake instead :doah:

No tuner lined up yet. There are several in my area but I'm not sure if any of them deal with TPI.

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Is the tpi really worth all that??
For the cost of the vortecs you could brand new blueprint or summit aluminum heads and get a new standard intake manifold. By the time you find a tpi tuner and pay to have it tuned you could just do a carb and be money ahead.
 
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