Building an engine for a cabin cruiser boat

Sick4qwik

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I'm also building my first 350.im debating on putting vortec heads and a cam or building a 383.im curious about your build suggestions hurst01.thanks in advance
 

hurst01

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Ok, let me try to explain some things here. I am a big fan of the 383 stroker engine. I can build a nice 383 stroker engine for just a smidge more than a stock 350.
A 383 Stroker is nothing more than a 350 bored out .030 to 4.030. The stock 350 has a stroke of 3.48". The 383 has a stroke of 3.75", an increase of a smidge over 1/4", or 0.270". This might not sound like much but it is only 0.010" shorter than a big block 396 or 427 Chevrolet engine. This will give tremendous torque. It is great in hot rods or street cars and also is a real performer in trucks that you might happen to pull a trailer with. It really requires no high performance intakes or carburetors, but really responds with them. It is just a good way to get torque. The information you are about to read is basically for a low RPM engine (under 6000 RPM)
I like roller cams... they just free an engine on response to acceleration, turn easier, have less friction, and typically will get better fuel economy.
I recently went to a local parts salvage yard. And purchased an engine from a 1997 Chevrolet Tahoe. Normally, the SBC block requires extensive grinding to get the larger stroke crank to clear the block. I was able to drop the 3.75" crank in the block with no grinding of the block. My rods cleared the block with a clearance of 10-15 thousandths. Not good! You need to clear the block by at least .020". It took only minutes to grind the additional .010" that I wanted for the crank to clear like I wanted. This was a very pleasant surprise. All I had to do then was to take the block to the local automotive machine shop for having the block bored and honed to 4.030", hot tanked, expansion plugs and cam bearings.
There is two ways you can go about this. You can bore the block .030 for a bore of 4.030, making it a 383 cubic inch, or you can leave it a stock bore of 4.000 and have a 377 cubic in engine with the same 3.75" crank.
This crank originated from a Chevrolet Small block 400. The small block 400 had a very short rod that would cause the bottom of the piston to be "thrown" from side to side causing piston skirt wear. The short rod was due to the deck height of the location of the wrist pin in the piston. Old-time builders would have the crankshaft turned from the SBC 400 rod and main diameters so that it would accept the stock bearing size of the SBC 350. The new "383" 3.75 " stroke cranks are cast with the correct diameter to accept the rod and main bearings of the 350 SBC, which save a lot of $$$$. The cast cranks will work fine for a low RPM engine. If you are going to be turning 7500 RPM then I suggest a forged crank.
I was a distributor of the 383 stroker kits but my source developed problems and could no longer supply me with the kits at a decent price so I quit selling them. Now, keep in mind the Chevrolet began installing the factory roller cams in the SBC around 1987. By using the 1997 engine block I was able to have the block already set up for a roller cam which saved me some money. Also, the later SBC Chevrolets used a different alloy block in combination with the hypereutic pistons and 1/16" thick low friction compression rings. I have torn down late model SBC engines with as much as 150,000 miles and still be able to see the factory hone marks. When you can see the factory hone marks you can be fairly assured the cylinder wall is not tapered, or is well within specs to use without boring. This is where the beauty of the 377 cubic inch comes in because you won't have to bore the block. A lot of people will dispute this, but I have had excellent results without honing a block that I can see the factory hone marks in. I get better oil control also. You will see opinions from both sides of the fence on which is best. I am just saying that I have had better results without honing.
By looking on ebay you can find some really good bus on a 383 stroker kit, as low as $750 with free shipping. The kit will come with pistons, rods & main bearings, crankshaft, and sometimes timing chain, cam and lifters. When they come with the lifters it will be with hydraulic flat tappets, not rollers. I don't go that way. You can find one that is used for the SBC 5.7 LT1 engines, but for a 383 stroker. They won't come with timing chain, gears, cam and lifters.
First, a word about Blocks: There are those that talk up the 4 bolt main blocks and talk down the 2 bolt main blocks. Let me tell you something... There has been some big name racers that ran the 2 bolt main blocks up to 10,000 RPM a long-long time before the 4 bolt main blocks were ever heard of. Being a 4 bolt main won't make it run any faster. Once you get the oil pan on you can brag all you want about it being a 4 bolt main if you want to.
Timing chain: I despise the whine of the gear-drive timing set mentioned in the above post. I don't like anything that sounds like it is trying to wear through my timing cover. I prefer a good double roller chain and gears that run quiet. If I have a lot of racket, I want it to be the sound of the cam and the tires breaking loose. The noisy timing chain wont make it go any faster. Different strokes for different folks, I guess.
Oil pump: Get a good high volume Melling pump and new screen.
Heads: The later model 5.7 engines came with center bolt valve covers, a lot were Vortec. These heads are more than sufficient to produce Butt-Loads of power without having to spend big bucks on them. Or, you can possibly run across a set of late model aluminum heads from a Z28 that will have excellent results. You can find a decent set of aftermarket aluminum heads on ebay for around $750 delivered with high performance springs of your choice. Larger valves can produce higher horsepower at higher RPM. Smaller valve will produce higher torque at a lower RPM and get better fuel economy.
Intakes: There are some very good intakes available, some are the Performer RPM, Weind Stealth, and others that were patterned after the 1969 302 Z-28 that had excellent flow characteristics, would give good horsepower and torque. They can be bought for $40 for a used one on ebay or up to $250 for a new one. They can also come with spacers for adapting the intake to the later model heads with the different bolt patterns on the intake ports.
Carb: There are many carbs that will perform admirably. The original Q-jet carb when properly tuned is no slouch. If you want to put a bit more money into one you can go with a Holley or Speed Demon.
Lifters: Lets be honest, a set of stock Chevrolet hydraulic roller lifters can last up to 200,000 miles with no problems. There has been times when the old pocket book was a bit thin and you do what you have to do when you need to do it. I recently bought several new sets of Delphi Hydraulic roller lifters on ebay for $95 with free shipping. The stock lifters are easily good for 6000 RPM.
Cams: If you are trying to save a few bucks you can go with a factory high performance cam such as in the late 80s Z28 or you can purchase a good aftermarket high performance cam. I have purchased several good Comp Cams with my desired lift and duration, new in the box for under $200. Just keep in mind with a larger lift cam you will have to replace the valve springs because the stock ones will handle just so much lift. (See Heads above)
Rocker Arms: I am a really big fan of full roller rockers if at all possible. Think about it, there is a lot of friction on a flat tappet cam between the cam lobe and valve stem. Anything you can do to help eliminate this friction is going to give better horsepower and engine response. A good set of PRW roller rockers will do an excellent job and clear the center bolt valve covers without the use of spacers. The stock rocker arm ratio for a SBC is 1.52, or more commonly referred to as 1.5. You can add a set of 1.6 roller rockers and it multiplies the cam lift by .08-.10. This can be substantial for the right combination.
The above is just a few ideas as to doing a low budget, back-yard build that will easily produce in the area of 400+ HP and up to 430 Lbs of torque. If you bide your time and shop around you can find some excellent deals. It would not be out of the question to do a low budget build for $1200-$2000, depending on whether you find some good usable parts and are able to do your own work or not. The engine I mentioned above was purchased from the local Pull-A-Parts lot for around $145 complete with starter, alternator, flywheel and all. If you want to stick with your original fuel injection if you have it, that will work too.
When you get started you can contact me and I can give you some pointers as you go.
Another way you can do it is to buy everything new and spend $4000. The best thing about roller cams is there is very little wear and they can be reused if you find the right grind that you want. I have also purchased reground cams on ebay for around $100 that work just fine. If you have deep pockets and want to go new with everything, go for it. Once you get the valve covers on it no one will know anyway.
I see a lot of people on the forum and their ride is a pick-up truck, sometimes up to a one ton. I don't know of anyone that will put a fortune in an older truck for an engine. But, on the other hand, there is a lot I don't know. The last 383 SBC I built was around 540 horsepower, but I didn't do a low-budget build. If you ever hear of HURST ENGINES, it is mine.
 

Sick4qwik

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I'm building the engine for a cabin cruiser boat I bought.it was a salt water boat an the oil pan rusted out on the guy I got it from.with boats being all about torque the 383 is going to be perfect.i don't think ill ever get close to 6000 rpms so the stock rods and pistons should be fine for my budget build.im gonna start looking at salvage yards for a vortec engine.i bought a holley 750 carb and an intake so far.i found the holley carb on eBay really cheap then after I bought it I read a few posts somewhere that a 750 was too big for a 350.since I'm building a 383 do you think it will be too big.thanks again
 

hurst01

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With the right cam you can run anywhere from a 650 to a 750, but I would not recommend anything larger. You can always take it off and get a smaller carb, especially since you already have it. I would prefer the 650 for fuel economy. With the 383 you could turn a larger (more pitch) prop.
 

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