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383 engine build question


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I have a lower end built for a 383. The block is from a 97 Suburban. I want to use Patriot aluminum heads. I want roller rockers as well, and the block is already designed for roller lifters. My question comes from looking through Summit and JEGS. Most everything listed will say "up to 87" or "87-95" for the heads and other things. Should I use parts for 87-95?

Are there any differences from this particular 97 block and all the listings for aftermarket parts

I own a regular repair shop, so doing any of this is not a problem. My experience is just fixing everyday cars with stock parts. Not making something from scratch and making sure its done right the first time. I'm sure everyone agrees, its no fun going through this much time and expense, and having to repeat it all over again.

There is alot of good stuff here, and I have already done a bunch of searching. But I have not seen something like this discussed.

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I have a lower end built for a 383. The block is from a 97 Suburban. I want to use Patriot aluminum heads. I want roller rockers as well, and the block is already designed for roller lifters. My question comes from looking through Summit and JEGS. Most everything listed will say "up to 87" or "87-95" for the heads and other things. Should I use parts for 87-95?

Are there any differences from this particular 97 block and all the listings for aftermarket parts

I own a regular repair shop, so doing any of this is not a problem. My experience is just fixing everyday cars with stock parts. Not making something from scratch and making sure its done right the first time. I'm sure everyone agrees, its no fun going through this much time and expense, and having to repeat it all over again.

There is alot of good stuff here, and I have already done a bunch of searching. But I have not seen something like this discussed.

 

The '87-'95 blocks are nearly the same as '96-'99 blocks. The latter has roller lifters, one-piece rear main seal, and used the Vortec fast burn cylinder heads. Please take a look at the Dart Pro1 Platinum Aluminum Cylinder heads. These have the latest wet flow testing of the port design. With the proper camshaft, cylinder heads, intake and carb is capable of getting 500+HP and 500+FtLbs of Torque. Also please consider ceramic coating the tops of the pistons and slippery coating the skirts. Also the exhaust port, cylinder side of intake and exhaust valves ceramic coated to prevent heat penetration into the piston and valves and migration of heat from the exhaust to intake port. Just some ideas.

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I already have the rotating assembly installed. I got an Eagle Products balanced set. The sides of the pistons are coated, but not the tops. I will look into those heads and look into the valves. I dont want a loping V8. I would rather keep it smooth.

Is a 110 lobe seperation fairly smooth, or should I go 108?

Super Chevy built a 383 using the same main parts (rotating assembly, Patriot heads, dual plane intake) and got 425hp on an engine dyno. It was a 3 part build up in last falls issues. Dont remember the specifics like cam, or carb.

Thank you.

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The 108 will lope alot more than the 110, which lopes alot more than a 112 IMO. The 110 and 112 will provide a wider torque curve, but the 108, 106 and 104 will produce a narrower one respectively.

 

IMO not knowing your intended usage, but based on your description only, I would go with the 110 LSA.

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I am inclined to believe that the most important part about selecting a cam is choosing the appropriate valve opening and closing events to meet your goals. The LSA and duration should be consequences of these choices, and not the other way around.Now of course, to appropriately choose the valve events you must know the flow characteristics of your heads and intake and also which harmonic wave you are tuning to (pertaining to the incoming air). The goal is orchestrate the valve movements to where the intake valve is opening just as the momentum of the incoming air is shifted towards the valve and then have it snap shut just as equilibrium is reached between the cylinder and intake runner (usually just after BDC).Proper cylinder filling is the only way to make horsepower to your engine's potential, and with the right setup you can see volumetric efficiency well over 100%.I must add that a lot of these ideas are based on wide open throttle and part throttle operation can throw in many different variables. Also, these are ideas that I have gleaned from people much more wise than myself and therefore I may have left out some small bit of crucial information. It is in your best interest to seek the help of a talented cam grinder and or head porter.On a side note, I agree with the idea of using the Dart Pro 1 heads, they seem to give most people excellent results and they apparently flow great straight out of the box.

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Thanks for a great description. I will go through those links as my time permits. I can easily see there is alot of info from those.

I am not looking for a drag car style engine. It will be a street car and maybe a few runs on the strip to see where it falls. I'd like a broad power band, and I dont have a tendency to run the piss out of things.

My compression ration with the rotating assembly is suppose to be 9.8:1 using 62cc chambers, 2.05 intake/1.6 ex valves from the Patriot aluminum heads which I believe are 210cfm. I know the Dart heads are suggested, but the Patriots are what I was starting to base the build off of.

I apparently had it backwards about lobe seperation. I thought 112 would be a lopey idle. So its the lower numbers that make the lopey idle, right?

I prefer to have a fairly smooth idle.

I'm open to suggestions as what cam grind to use, but will definetly go through those links to "broaden my knowledge". Thanks guys.

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I apparently had it backwards about lobe seperation. I thought 112 would be a lopey idle. So its the lower numbers that make the lopey idle, right?

I prefer to have a fairly smooth idle.

I'm open to suggestions as what cam grind to use, but will definetly go through those links to "broaden my knowledge". Thanks guys.

 

LSA is the lobe separation angle measured between the exhaust and intake centerline. The closer those are together (less LSA) the more overlap you get on the intake and exh valves and correspondingly a rougher idle.

 

If your looking for a decent idle then you'll be looking for a 112 LSA. Some or most hot street cams come with a 110 LSA.

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