383 in My Cutty

[86Cutlass383SR]

jonnyv713 for a true street engine, those 225 heads aren't really worth it. You want a head to keep the intake charge velocity up. Those heads will flow good, but at higher rpm's than you'll be likely using on a street engine. At lower rpm's, the intake flow will be lazy and make the engine a complete dog at cruise speeds.

Look for heads in the 180 - 200 cfm range.

BTW, with my 385 I'm running EFI, 10-1 compression (in case I run into an occasional batch of bad gas), AFR 190 heads, and a hydraulic roller of 230*/236* on a 113 LSA (for my fuel injection). My quench is a bit higher than I'd planned at .050" due to my machinist not zero decking my block like I'd wanted. I didn't know this until AFTER I had the engine back...

Last time I have someone else build my engine...he offered me a good warranty for a good price otherwise I'd had assembled it myself ...

 

[jonnyv713]

So, I really cant measure quench and everything until i get it put together can I?

And, the Trick Flow heads that are 195cc are about right?

 

[86Cutlass383SR]

So, I really cant measure quench and everything until i get it put together can I?

And, the Trick Flow heads that are 195cc are about right?

Measure, no. But you can calculate it close enough for a street engine. Since you have the block machined already, mabe the machinist can tell you the deck height. The stroke will be 3.75", the rods will be either 5.7" or 6", and the pistons you choose should have the piston height listed (this is the distance from the centerline of the wrist pin to the top of the piston). The rod length will determine the pistons you choose. Most of the time, the piston height will be for a block decked to 9" even, but not always! 1/2 the stroke (1.875") + rod length (either 5.7" or 6") + piston height. Should be around 9" - 9.010". Subtract the block deck height and that will be how much the piston is either down the bore or above the deck.

For example only, here's what my engine figures out at so you can see how to calculate it.

Block deck height = 9.017"
Rods = 5.7"
Stroke = 3.75"
Piston height = 1.433" (KB hyper)
Gasket compressed thickness = .041" (FelPro 1003)

1/2 the stroke + piston height + rods
1.875" + 1.433" + 5.7" = 9.008" installed for the assembly. Subtract the deck height of 9.017" and the piston is .009" down the bore. .009" + the gasket thickness of .041" and that gives a quench heght of .050". (I never thought I'd use math after I got out of school... )

The Trick Flow 195's would be a good choice for you.

After you decide on a cam, I'd call a few torque converter companies and give them your engine specs and intended application for a recommendation on a torque converter ... unless you decide to finally go with that manual transmission... LOL!

 

[jonnyv713]

I had the machine work done a while back. I don't think the machine shop will know those measurements anymore. I have a local shop thats closer than the one i used for clearancing and boring. Could I just take it to the closer one and have the deck zeroed out? Thas what i want to do, right?

 

[86Cutlass383SR]

Well, in that case, I'd just go ahead and get the crank,rod,piston assembly of your choice. You will want to do a mockup assembly anyway to make sure everythings clears. You could have the block checked for deck height at that time. If the pistons are down in the hole (and by how much) you can decide if it's worth re-cutting the deck or not. If your pistons are in the hole, say for example, .010" to .005", it wouldn't make sense to pay to have the block decked again. Just get a thinner head gasket and the same results will be obtained.

If the pistons actually stick out of the block, you can measure how much, and contact the piston manufacturer to see it's safe to cut the top off the piston by that much. As the example above, if they stick out by the same .010" - .005", a thicker head gasket can be used.

Remember, also, that where the piston sits in the bore will affect the compression ratio. If you use a thick gasket, it will reduce the compressin ratio and if you use a thinner gasket, it will raise the comp ratio. Small changes can make a big differance. That is also why I only ran 10-1 compression ratio. I bit on the low side will have much less impacr on performance than a bit too much. Too much can equal big problems!

A good machinist can help guide you to those decisions. I'd seek out a good performance machine shop. A stock type machinist *may* not realize the advantages/disadvantages to mininumizing the quench height. Not saying they aren't a good choice, just read up on quench and after you understand it, talk with them and see what they say.

I will help all I can when you get to that point. I would still verify with a machinist. One other point I'd like to make. When you do your engine mockup to check for clearances, install your cam that you are going to use with the timing chain. Slowly rotate the engine and check for clearance between all cam lobes and rods. Certain cam lobes get very close to some rods. That's why some people recommend using a small base-circle cam but I've never had a problem. Yes, some rods will need clearancing so make sure you have all this checked *before* you have the rotating assembly balanced.

Until you actually start building an engine you probably never knew it was such a close tolerance machine. Most people just see a big ole lump of iron and don't know just how much of a precision peice of machinery. Just take your time and don't get in too big a hurry. If something don't look right or measure out, ask questions. Don't just throw it together. The more time spent here now will result in the best, longest lasting (and most satisfying!) result of your building experience.

 

[jonnyv713]

I called my machine shop today and they basically said the same thing that you said. They said bring it down with the rotating assembly put in and he could make it flat with that. It would cost $160 though. I was also thinking about the gasket thickness like you said, too.

I think its time to start ordering parts as soon as money is right. I REALLY appreciate your patience and help. I'll let you know what goes on.

 

[86Cutlass383SR]

Here's some good books to read that will really help clear up a lot of questions. Not that I mind helping, it's just the more you understand youself, the better you'll know what you want and how to get it.

These cae found at amazon.com or if you have a Barnes & Noble. You may even find some to check out a bigger local library.

Here's the first one I'd recommend getting (RIP John Lingenfelter...): http://www.amazon.com/John-Lingenfelter ... 406&sr=1-1

and then anything written by David Vizard. Here's just a random sampling of good reads:

http://www.amazon.com/How-Rebuild-Your- ... 504&sr=1-1

http://www.amazon.com/Build-Small-Block ... 504&sr=1-2

http://www.amazon.com/Rebuild-Small-Blo ... 504&sr=1-3

http://www.amazon.com/Small-Block-Chevy ... 04&sr=1-12

http://www.amazon.com/Build-Performance ... 240&sr=1-5

 

[86Cutlass383SR]

I think its time to start ordering parts as soon as money is right. I REALLY appreciate your patience and help. I'll let you know what goes on.

I'm all too glad to help. That's why we're here, to help each other. Someday, you'll be passing the same info along just as I have. It's all about giving.

Never hesitate to ask...

You better keep me posted !!!

 

[86Cutlass383SR]

I called my machine shop today and they basically said the same thing that you said. They said bring it down with the rotating assembly put in and he could make it flat with that. It would cost $160 though. I was also thinking about the gasket thickness like you said, too.

I think its time to start ordering parts as soon as money is right. I REALLY appreciate your patience and help. I'll let you know what goes on.

Sorry if I just keep rambling on and on...I just really like this engine stuff!!! Hey, you got me started LOL. I have a few more points I'd like to make if I may...

I would assemble it and measure it yourself. Buy the tools you need and measure yourself. Measure again...ask questions...(measure again...) and you'll know if you need to spend that $160. You may only need to vary your gasket thickness.

A few points to help in your rotating assembly purchase. First and foremost, be honest on how you are going to use the engine. Will it ever see nitrous, turbo/supercharging, high rpm's (over 6000), street use or drag racing, etc. Evaluate what you want to build. Only YOU can answer these questions.

Hyperutectic pistons can be fit to the bores tighter than forged pistons can. Longer life. Stronger but more brittle than forged. The higher silicone is what makes this possible.

Forged pistons can take more abuse than hypers. They can deform more without breaking (flex). This elasticity is what makes them desirable for nitrous and blown applications, etc. They can slightly deform before breaking. Forged pistons expand more when heated and this is why they need more cylinder wall clearance.

Pistons tops: Domed, flat top, and dished. Don't use a domed piston due to poor flame travel across the top of piston. Use a smaller combustion chamber instead. You can still build over 13-1 compression (not that you want yours that high!) with a flat top so there's no reason to use a domed piston. A flat top is good. Nice even burn across the top of the piston. I actually used what is called a "D" - dished piston. The flat part is in the quench area to keep a good quench and the dish allows more room for turbulance to keep the air/fuel mixed up. It's all just theory so I thought I'd try it. Not much time for all this to happen at 2000 - 6000 rpm so I'm not positive on if it really works... we'll see I guess.

I decided to keep my compression a bit lower. Reason: It will be a daily driver that I plan on taking on road trips. 600 - 1000 mile round trip road trips. Gas quality won't be as big a concern if I get a bit of bad gas or I have to use a slightly lower grade in a smaller town. With my alum heads and timing control and the better atomazation of fuel injection, I could've went as high as 11-1 but decided to hold off at 10-1. Reliability over horsepower in my case.

Rings: 1/16" or 5/64" 1/16" rings seal better over 6000 rpm. I chose the stock thickness of 5/64" again for reliability.


I just noticed I signed on exactly 1 year ago, almost to the minute... and this is post number 442 for me

I know...I'm wierd like that

 

[jonnyv713]

Ramble as much as you want. I love learning about this stuff. Thank you.

This car will be on the street most of the time. It will hit the strip on the weekends maybe. I just want to have a mean street machine that'll make the mustangs shut up at the track!

Nitrous.... Maybe a sneaky pete system under the seat or something just for a little cheat or something if I need it. Maybe not if the motor won't be able to handle it. Turbo or supercharging... probably not. If I ever supercharge anything in my lifetime it will be a dedicated drag car, and I will be going all out. I mighta missed a couple of your questions. let me know if I did.