what pistons to run with set up??a bit of help

-
Y

Youngthrill

69 GT
Joined
Jan 20, 2012
Messages
96
Reaction score
1
Location
Berkeley
so i have a 318 going .30 over would love to run edelbrock 60779 heads..but a bit out of budget or i can get some #302 rebulit heads for half the price.. what will the power differance be??

now i came across the kieth black kb399-030 pistons and kb167-030..
one set has domes ..which ones should i run ??looking to build a good street monster...picking up a cam with about 4'7 lift 268 duration...

but one step at a time have to make the right piston choice, im running a 273 forged crank ...any though on this help??all help welcomed..:)
 
I would not run either set with the 302 heads. You will have too much compression. If you stick with the stock 4 eyebrow pistons, you can get to 9.5:1 with some light head or block milling. That is all you will be able to stand without building an expensive quench motor.
 
i have to bore the block, should i get one of the kb sets i mentioned and run stock heads ??...
if i can do that it will save my pocket quite a bit..if so besides springs what should i get done to the heads??besides new valves and seats..thanks i know its alot of help but im new to this preformance combanation stuff
 
The KB 167's and 302 heads are a pretty popular combo. Have the block zero decked, and you'll end up with 9.5 or so compression. Make sure there are no sharp edges in the chambers and you should be fine on pump gas.

I would at minimum upgrade to 360 valves, and do a basic bowl blend and gasket match. With a fairly mild cam like an XE268, reasonable carb, intake and exhaust, 325 HP at the back wheels should be easily possible.
 
Youngthrill said:
so i have a 318 going .30 over would love to run edelbrock 60779 heads..but a bit out of budget or i can get some #302 rebulit heads for half the price.. what will the power differance be??
Click to expand...

Depends on head flow and properly sized head ports for the engine at hand. Big ports do not always mean big power. On the dyno, in the past we have had big port engines make great power, but, they also got there clocks cleaned by smaller port heads in the same size engine. (Sometimes with a smaller cam as well.)

now i came across the kieth black kb399-030 pistons and kb167-030..
one set has domes ..which ones should i run ??looking to build a good street monster...picking up a cam with about 4'7 lift 268 duration..
Click to expand...

The 167 is fine for street and light strip. No dome's for you.
 
So kb 167 it is!! can I run a lets say xe284 duration with stock heads? What size valves should I run with this cam???
 
I have told you once, the KB167 will give you too much SCR. With 60 cc heads, zero deck height you will have 10.55:1. That is way too much for pump gas, but have fun, ya hear?
 
StrokerScamp said:
I have told you once, the KB167 will give you too much SCR. With 60 cc heads, zero deck height you will have 10.55:1. That is way too much for pump gas, but have fun, ya hear?
Click to expand...

Unless the cam be BIG!
 
You really need to find out what the 302's chamber size is, I found some of them at 64cc and correct me if wrong but with a standard FelPro head gasket and kb167 piston
( 5cc valve relief) zero decked...You have quench and 9.5 to 1 compression...Perfect Harmony.......even at 60 cc chamber 10 to 1 compression....
 
I'm building this car for fun to not to daily drive...I just want to be able to run pump gas and not have motor pinging issues .....can 10.55 to 1 be ran on the street????strokerscamp Ive read some of yours and rumblefish360 threads I can say both of you know your stuff...and still I have not yet purchased pistons!!

Anyone ever use aeroheads???67-70cc open chamber if so how are they
 
Lot's more to whether it will work than the comp ratio needed,but from the hip,NO it's too much. Lot's of cam isn't the correct answer either. With the crappy and inconsistant fuels available at the pump you should stay lower than the internet gurus recommend as any POSSIBLE gains will be crushed with retarded timing to live. Lots of gear ,converter,light weight,etc may help your combo,but I'm not going to recommend it to someone that has to ask on the net.
 
12 to1 can be run on 87 octane just not when the throttle goes to the floor(unless you've really f'ed up). Good luck with your build.
 
IMO, honestly, you need to do some looking around and find a set of slugs that will make a 9.5-1 ratio at max with the head your going to use. You need to find out the cc amount of the head your going to use. Then, combine all of these numbers to find out what gasket to use.

While the KB-167 can be used for the street, the ratio it produces with a small chambered head will be high. In general terms, but not in stone, a street pump gas friendly ratio for a iron head is 9.5-1 and 1 point higher for aluminum. You can get away with more compression is the cam gets larger to bleed off compression.

If the cam gets larger, other considerations must be taken. Higher gear ratio, stall converter are the start.

There are a few unknowns to this whole thing that you are missing and the engine is only part of the deal.

While my answer of a bigger cam will allow the engine to run on a high compression ratio, it isn't exactly the best answer to the problem, there is truth to it. But it may not be what you want to do. The answer is correct to a degree. Lets find out what degree your in.

Tell me, what is the gear ratio, tire size, tranny's stall converter or 4 spd.
We have intended purpose all ready, it is a fun machine that runs on pump gas.
 
rumblefish360 said:
Depends on head flow and properly sized head ports for the engine at hand. Big ports do not always mean big power. On the dyno, in the past we have had big port engines make great power, but, they also got there clocks cleaned by smaller port heads in the same size engine. (Sometimes with a smaller cam as well.)
Click to expand...

Their clocks cleaned how? Sounds interesting. Was this a direct head to head comparison? Could you be a little more specific with the examples? Engine size, engine type (Ford, Chevy, Mopar, big block, small block), intake type, head type, valve size, airflows, port volumes, camshafts, carburetion. I too have heard of this, but have never seen any actual tests.
 
IQ52 said:
Their clocks cleaned how?
Click to expand...
Your kidding right?

Sounds interesting. Was this a direct head to head comparison?
Click to expand...
As close as you could unless you yourself built both engines for the comparo.
Could you be a little more specific with the examples? Engine size, engine type (Ford, Chevy, Mopar, big block, small block), intake type, head type, valve size, airflows, port volumes, camshafts, carburetion. I too have heard of this, but have never seen any actual tests.
Click to expand...

Nope. But I do think you know what I mean and your just fishing around for something.
You know as well as I know that there is always a better way to skin a cat. Thus, building a better engine, more thought out than just shove in the biggest cam in the book, slap on the biggest flowing port windowed heads in the book, getting the largest Holley listed, etc....
Click to expand...
 
It's just a fallacy to think you can get away with even a blueprinted 9.5 on pump gas without some kinda quench. You caint do it. Not with iron heads. You wanna set up an expensive quench motor where you have to individually massage each cylinder's piston and combustion chamber? Great. Knock yourself out. But the average joe motor ain't gonna run pump gas with 9.5. I have a friend who has a SHO NUFF 71 LT-1 Camaro. engine's never been into. Has like 65K original miles. It's rated at 9.2:1 just like it left GM. Even has a pretty stout factory solid cam. Without a spike of at least 5 gallons of 114 Cam2 racing fuel it rattles on today's super. It has a sticker on the sun visor that says "PREMIUM FUEL ONLY" and that was back in 1971, not today with the crap gas we have. Premium fuel in 1971 was 101 octane. 105 in some places. My friend's 86 D150 he has KB167s in will rattle when it's hot if he lugs it in too high a gear at to low a speed with his 4 speed OD. Build your motor at 9.0:1 if you wanna run on pump gas with no quench without a ridiculously sized camshaft.
 
StrokerScamp said:
It's just a fallacy to think you can get away with even a blueprinted 9.5 on pump gas without some kinda quench. You caint do it. Not with iron heads. Build your motor at 9.0:1 if you wanna run on pump gas with no quench without a ridiculously sized camshaft.
Click to expand...


I don't agree. I've had as high as (calculated) 10.8:1 with no quench. It's about understanding everything and how it works together, and providing the circumstances where it will work. For an average 318, average machining, and average garage guy tuning and building, 9.5:1 is fine for a cam over 225° @ .050. If the plan includes power brakes and demanding a smaller cam, then yeah you will want to keep the compression conservative if you have to run open chamber heads. But it's not impossible. It's fairly common to run 9 to 10:1 on open chamber heads with the right cam and setup.
 
moper said:
I don't agree. I've had as high as (calculated) 10.8:1 with no quench. It's about understanding everything and how it works together, and providing the circumstances where it will work. For an average 318, average machining, and average garage guy tuning and building, 9.5:1 is fine for a cam over 225° @ .050. If the plan includes power brakes and demanding a smaller cam, then yeah you will want to keep the compression conservative if you have to run open chamber heads. But it's not impossible. It's fairly common to run 9 to 10:1 on open chamber heads with the right cam and setup.
Click to expand...
I agree with this post!!
 
moper said:
I don't agree. I've had as high as (calculated) 10.8:1 with no quench. It's about understanding everything and how it works together, and providing the circumstances where it will work. For an average 318, average machining, and average garage guy tuning and building, 9.5:1 is fine for a cam over 225° @ .050. If the plan includes power brakes and demanding a smaller cam, then yeah you will want to keep the compression conservative if you have to run open chamber heads. But it's not impossible. It's fairly common to run 9 to 10:1 on open chamber heads with the right cam and setup.
Click to expand...

Remember, gas is not the same in all parts of the country. Disagree all you want, there are enough variables either way for you to be wrong and me to be right.
 
It can be done, I run 9.7 measured compression on 87 octane in my truck. That's with shallow open chambers (no quench), a short duration cam, and aggressive advance curve. Careful chamber prep, cold plugs, proper jetting and oil control all help. At 2800 MSL, I have elevation on my side as well.
 
"careful chamber prep". Exactly. It ain't cheap, unless you can do it yourself. BUT ONE MORE TIME...and see if yall can grasp it. I am talking about completely unmodified chambers, pistons and everything else. I am talking about what most build on a BUDGET. WIthout a big camshaft that totally WASTES cylinder pressure, you cannot do it. Without "careful chamber prep" AND careful piston prep, you cannot do it. I don't give a FRIG what you've read, been told or otherwise. Here's the bottom line. If you have made an engine run on pump gas above 9.5 you have either one of two things:1) a stupid overcammed inefficient pile of iron, or 2) you have done all that careful prepping people here have talked about. PERIOD.
 
rumblefish360 said:
Your kidding right?

As close as you could unless you yourself built both engines for the comparo.


Nope. But I do think you know what I mean and your just fishing around for something.
You know as well as I know that there is always a better way to skin a cat. Thus, building a better engine, more thought out than just shove in the biggest cam in the book, slap on the biggest flowing port windowed heads in the book, getting the largest Holley listed, etc....
Click to expand...

Fishin'? Yep, always fishin'. For facts. Like I said, never seen them tests. Wondering WHEN that port gets too big on whatever engine. Guys warning 'bout too bigga ports all the time. How's them Edelbrock 60779 ports? Too big? Too small? Or just right for his 318? Why? How much head can he put on the 318? Anybody test them Eddy's agin the 302? Can anybody point him to a test that someone else has done?
 
I betcha StrokerScamp could build a 87 octane, 12:1 motor with no quench if'n he had a mind ta'. But I'm shore with him for this build. Don't know this builders level of expertise, but don't you think it sounds like 9:1 would be smarter for a person without more experience? The guys callin' for more compression sound like they have enough knowledge to choose their own heads and pistons. Keep it safe for this guy.

Endeavor to persevere Stroker.
 
IQ52 said:
Fishin'? Yep, always fishin'. For facts. Like I said, never seen them tests. Wondering WHEN that port gets too big on whatever engine. Guys warning 'bout too bigga ports all the time. How's them Edelbrock 60779 ports? Too big? Too small? Or just right for his 318? Why? How much head can he put on the 318? Anybody test them Eddy's agin the 302? Can anybody point him to a test that someone else has done?
Click to expand...

I would also like to know when a post gets to big for a given displacement. However, common sense is a good guide in many applications. To that end, (Back to the prior statement/question) When is an Edelbrock head good for a 318? While still a broad question, it would have several questions to go with it before a actual build is to take place. Building a well rounded package is the key and missing info should be a known.

The engine should work well in car, not just dyno'd and with great numbers. What works well on a dyno may not work at all in car.

Chrysler did a dyno comparo between 302 heads ported and 360 heads. (IIRC, unported) and found the 302 head to make 55 HP more. This is by now, very old info. I'll try and find the article for the build parts.

IQ, please take a little bit of time to correctly quote, use the quote feature and/or use the edit button to fix quotes you use in your post. Thanks.:thumbup:

IQ52 said:
I betcha StrokerScamp could build a 87 octane, 12:1 motor with no quench if'n he had a mind ta'. But I'm shore with him for this build. Don't know this builders level of expertise, but don't you think it sounds like 9:1 would be smarter for a person without more experience? The guys callin' for more compression sound like they have enough knowledge to choose their own heads and pistons. Keep it safe for this guy.

Endeavor to persevere Stroker.
Click to expand...

Agreed, it is hard to help in a thread when a general question is posted without enough info. General question gets a general answer. Details to help the problem get a detailed and/or a better answer.

While a person could build a 12-1 engine to run on 87 octane, this maybe the worst way to go for this person and there intended purpose usage pf the car.
Stroker makes a good point and you as well, but, the OE thread starter needs to reply with the above questions answered for a great reply, opinion, answer to this all.
 
IQ52 said:
I betcha StrokerScamp could build a 87 octane, 12:1 motor with no quench if'n he had a mind ta'. But I'm shore with him for this build. Don't know this builders level of expertise, but don't you think it sounds like 9:1 would be smarter for a person without more experience? The guys callin' for more compression sound like they have enough knowledge to choose their own heads and pistons. Keep it safe for this guy.

Endeavor to persevere Stroker.
Click to expand...

Thanks for the kind words. That means a lot coming from you, Jim.

Yeah, I've built quench motors before. ...and as I was tryin to point out, they ain't cheap. Probably not a good engine for a first time build or someone with limited experience or knowledge. A well thought 9.1 engine will make it's owner happy as a lark and run very well on crummy gas. ...and be a cheap build. Like my D150 motor for example. I am using .030 over USED 4 eyebrow flat tops. Going with magnum heads. I am gonna blueprint a 9.1 motor. Yeah, I could go 9.5 and higher if I wanted to but 1) this is a truck. I might end up towing something with it one day. 2) I want it to get some decent mileage. It may end up being my daily driver if I am lucky enough to find a buyer for my '04 Ranger. So, fact is I don't wanna even think about a motor that will even come close to spark knock. Yeah, I reckon I could polish the chambers, file all the sharp edges off the pitons and all that. But......I am actually going to put a stock bore and stroke 383 in that truck later on down the road.....so it's budget time. Hell....the little 318 might surprise me and get to stick around for good. Who knows?
 
You must log in or register to reply here.
-

Back
Top