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You don't HAVE to run higher compression with the aluminum heads, just you are able to run a bit higher compression without detonating.

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You can use the speedpros , you may have to cut valve reliefs in them, have the block cut so the pistons are at zero, have the heads cut to 80cc and you'll be at 10.0 , the flattop piston will be more efficient than the KB400 with a dome.

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I ASSumed the piston depth based off a measurement I took from the original pistons and then added the CH of the new pistons. I know I'm not going to know for sure until I get it back from the machine shop, which is why I haven't ordered the head gaskets yet.

I may go with headers, not sure which ones would fit or not. This is a manual brake, manual steering '68 Sat.

The gear is a 3.23 with a 2500 stall. That cam should be just a little larger than a stock HP cam, so I'm not sure why 10.5:1 CR is really needed?

I'm not going to be racing this thing at the drag strip. It's a pretty cheap car that I don't have much money invested in and felt like making something to cruise and go fast in every now and then.

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I usung the Summit headers on my 440-6. They fit w/o any problems. Even when I had PS. I'm also using a mini-starter.

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You shouldn't compare a 440 and starter clearance using a mini starter to a 383 , the headers are closer to the block on the 383. I TRIED to use a mini starter with a set of 1 3/4 primary headers and I couldn't get the header on the engine with a mini starter .

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Ok, I have parts, so this is pretty much the way the build is going to be, not much in the room of changing things around now...

I did as much research as I could....with the help of you guys

Anything with a "?" beside it is still not for sure...so I would need some input

383
.030 over
std rod/mains
ARP rod/main/head bolts
Edelbrock closed chamber heads
Cometic .027"/4.35" head gaskets (?)
SpeedPro 2315 (1.920" CH)
stock deck height (squared to crank)
balanced assembly
Comp XE 274/286 cam/lifters
Performer RPM intake
650 Thunder Series Carb (?)
MP igniton conversion kit
Factory HP manifolds (?....any issue with the angled plug heads? would rather not use headers)
Comp Double Roller

I'm getting 9.57:1 CR ASSuming the piston is .01 in the hole with the 2315 pistons. That would also figure a .037" quench as well....correct?

How does this sound to you guys?

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MP has the Eddy head in a straight plug, but it looks like you've purchased the heads already.

Get the CR to 10:1 to 10.2:1

I too prefer zero deck and a 0.040" gasket. You'll probably save $ on the gasket too.

I too like the Crower 271 cam.

I would use more carb cfm

You definately do not need 3" exhaust. It will probably hurt performance.

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Ok, I am not building a race car, drag car etc. I am purposely building this thing to cruise, especially the interstate and highways. I appreciate the info on swapping converters, gears etc. But I'm not going to do that, it is what it is and I did it for a reason....I already have a car with a 3200 converter and "only" 3.55's. It revs too high on the interstate as it is....3200 RPM is too noisy for my liking.

My main concern is the heads/piston/head gasket combo. I wasn't aware when building a 383 that piston choices suck. Not only that, but it sounds like my options are expensive pistons or expensive machine work. I just so happen to have the expensive pistons....however from what most people on here tell me that the CR will not be enough with my head gasket choice (if I get it....027") and my head chamber volume (84cc). So I am back to thinking of just ordering a set of KB400s which from what I have calculated should be very close to 10:1...but I could be and probably am wrong.

Once I get info from the machine shop of what the depth will be with the KB400's vs the 2315's I'll make a definitive decision. Supposedly the KB400's will be inefficient compared to the flat top 2315's.....whatever that means.

The gear stays, the converter stays, the cam stays....I will probably take everyone's advice on the carb, maybe even consider headers after I get some miles on it and feel like doing something.

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Ok, I am not building a race car, drag car etc. I am purposely building this thing to cruise, especially the interstate and highways. I appreciate the info on swapping converters, gears etc. But I'm not going to do that, it is what it is and I did it for a reason....I already have a car with a 3200 converter and "only" 3.55's. It revs too high on the interstate as it is....3200 RPM is too noisy for my liking.

My main concern is the heads/piston/head gasket combo. I wasn't aware when building a 383 that piston choices suck. Not only that, but it sounds like my options are expensive pistons or expensive machine work. I just so happen to have the expensive pistons....however from what most people on here tell me that the CR will not be enough with my head gasket choice (if I get it....027") and my head chamber volume (84cc). So I am back to thinking of just ordering a set of KB400s which from what I have calculated should be very close to 10:1...but I could be and probably am wrong.

Once I get info from the machine shop of what the depth will be with the KB400's vs the 2315's I'll make a definitive decision. Supposedly the KB400's will be inefficient compared to the flat top 2315's.....whatever that means.

The gear stays, the converter stays, the cam stays....I will probably take everyone's advice on the carb, maybe even consider headers after I get some miles on it and feel like doing something.

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The CH of the KB400 is 1.908 , the CH of the 2315 is 1.920.

You should really call the cam company and get their recommendation for the convertor a cam/rear gear mismatch can be somewhat masked by a 4spd , not some much with a automatic trans. ... edit , I just went back and reread, your convertor choice may not be that far off especially if you go with the 268.

What I meant by inefficient is the dome impedes flame travel across the chamber , a flat top doesn't . I am building a 383 based stroker with 12.5 compression and the only way to do it was either cut the bleep out of the heads or use a small dome , I chose the dome , should have cut the heads

You didn't buy the EXPENSIVE piston , that is the Diamond. You could have had the block decked , mock it up and ordered a piston that didn't require cutting a mile off the block, that's what I did with the 383 engine that I just recieved from the shop yesterday. But my block had already been cut a mile because of bad first piston choice, the 2315, and then shoddy machining by a couple of shops this block has passed thru till the latest. It's a 10.0 build with open chamber iron heads.

Do what you want , you asked for people to rate your build , you got it and it seems you don't like some of the answers you are being given.

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if you are worried about compression use the steel shim gasket. IIRC it crushes to .019.

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The CH of the KB400 is 1.908 , the CH of the 2315 is 1.920.

What I meant by inefficient is the dome impedes flame travel across the chamber , a flat top doesn't . I am building a 383 based stroker with 12.5 compression and the only way to do it was either cut the bleep out of the heads or use a small dome , I chose the dome , should have cut the heads

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I understand what you mean by the dome "getting in the way"....but how does that affect your car? Decreased performance? Gas Mileage? I was looking at getting the dome to help with CR since everyone was saying 9.5:1 wasn't enough for that cam. The dome would put it about 10:1.

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I understand what you mean by the dome "getting in the way"....but how does that affect your car? Decreased performance? Gas Mileage? I was looking at getting the dome to help with CR since everyone was saying 9.5:1 wasn't enough for that cam. The dome would put it about 10:1.

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In a perfect world the flame front would progress faster across a flat piston than one w hills but a flattop piston w enough CH to get quench will most likely give you too high of CR plus you'll need valve reliefs machined. Get the KB's w the quench plateau & mockup/machine to get quench (.040" max) plus the right SCR for your app

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I understand what you mean by the dome "getting in the way"....but how does that affect your car? Decreased performance? Gas Mileage? I was looking at getting the dome to help with CR since everyone was saying 9.5:1 wasn't enough for that cam. The dome would put it about 10:1.

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In a perfect world the flame front would progress faster across a flat piston than one w hills but a flattop piston w enough CH to get quench will most likely give you too high of CR plus you'll need valve reliefs machined. Get the KB's w the quench plateau & mockup/machine to get quench (.040" max) plus the right SCR for your app

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The thing is the dome isn't on the side where quench is obtained, it's in the chamber area... To get quench you need a closed chamber head which I believe is what the O/P is planning to run... So at the point quench becomes a function of how far the piston is in the hole & head gasket selection.... There are no off the shelf quench dome pistons for 383's...

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Ok, I am not building a race car, drag car etc. I am purposely building this thing to cruise, especially the interstate and highways. I appreciate the info on swapping converters, gears etc. But I'm not going to do that, it is what it is and I did it for a reason....I already have a car with a 3200 converter and "only" 3.55's. It revs too high on the interstate as it is....3200 RPM is too noisy for my liking.

My main concern is the heads/piston/head gasket combo. I wasn't aware when building a 383 that piston choices suck. Not only that, but it sounds like my options are expensive pistons or expensive machine work. I just so happen to have the expensive pistons....however from what most people on here tell me that the CR will not be enough with my head gasket choice (if I get it....027") and my head chamber volume (84cc). So I am back to thinking of just ordering a set of KB400s which from what I have calculated should be very close to 10:1...but I could be and probably am wrong.

Once I get info from the machine shop of what the depth will be with the KB400's vs the 2315's I'll make a definitive decision. Supposedly the KB400's will be inefficient compared to the flat top 2315's.....whatever that means.

The gear stays, the converter stays, the cam stays....I will probably take everyone's advice on the carb, maybe even consider headers after I get some miles on it and feel like doing something.

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I understand what you mean by the dome "getting in the way"....but how does that affect your car? Decreased performance? Gas Mileage? I was looking at getting the dome to help with CR since everyone was saying 9.5:1 wasn't enough for that cam. The dome would put it about 10:1.

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In a perfect world the flame front would progress faster across a flat piston than one w hills but a flattop piston w enough CH to get quench will most likely give you too high of CR plus you'll need valve reliefs machined. Get the KB's w the quench plateau & mockup/machine to get quench (.040" max) plus the right SCR for your app

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Robert , Robert , Robert , you appear to know NOTHING about 383's , you should sit back and LEARN from those that do ...

KB does NOT make a quench head piston for a 383 , never has and probably never will, so you need to stop suggesting that to people building 383's. Nevermind to get quench with a flat top and a closed chamber ... uuum , just zero deck , you zero deck and with 80cc head you end up with 10.0 , since the heads he wants to use are 84cc he's not going to have too high a compression ratio ??? It's not rocket science , the problem with a 383 and compression is the SMALL bore size and the SHORT stroke, combined it's hard to get decent compression.

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The CH of the KB400 is 1.908 , the CH of the 2315 is 1.920.

What I meant by inefficient is the dome impedes flame travel across the chamber , a flat top doesn't . I am building a 383 based stroker with 12.5 compression and the only way to do it was either cut the bleep out of the heads or use a small dome , I chose the dome , should have cut the heads

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What is the CH of a stock 383 piston? I can't remember but I thought it was less than the KB400 1.908.

I understand what you mean by the dome "getting in the way"....but how does that affect your car? Decreased performance? Gas Mileage? I was looking at getting the dome to help with CR since everyone was saying 9.5:1 wasn't enough for that cam. The dome would put it about 10:1.

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Depends on the year engine but the stock CH of the 68-69 383 HP (which is what i base all my on ) , and 68-69 2bbl for that matter , is 1.932 , this puts the piston .0025 in the hole on a factory deck height, the 2bbl piston has a dish. as delivered the HP was 9.2 at best. I've gone 100mph in the 1/4 with a 56K worn HP engine with a timing chain so loose it could be removed without taking off the gears ... almost... so it's not as bad as we are lead to believe.

One of the mags did an article on installing ebrocks on a 383 , they THOUGHT they had a piston close to factory CH. But when they pulled the heads it had low compression cast replacements, they were something like .050 plus below the deck , the engine was not the DOG they thought it would be, food for thought .

In the grand scheme of things you will probably not notice any difference with the KB400 so just ignore what I said about inefficiency .