A truly stock bottom end isn't going to yield as much compression as you'd think. The pistons are too far down in the hole, and it would take some seriously (maybe even impossibly) small chambers to get true 9.5:1 and up.I am getting ready to start a 318 build and would like to know how much compression a stock bottom end can handle and how much is achievable. It will be running on E 85 and will be race only.
I am planning on zero decking the block and running worked magnum headsA truly stock bottom end isn't going to yield as much compression as you'd think. The pistons are too far down in the hole, and it would take some seriously (maybe even impossibly) small chambers to get true 9.5:1 and up.
With stock pistons? You'll be cutting alot off the deck, some pistons have been measured .120" down in the hole. Why not get some pistons with a taller compression height, then you can zero deck those pistons.I am planning on zero decking the block and running worked magnum heads
I do plan on getting pistons, just wondering what the stock crank and rods will handle. Trying to get the most out of it on a small budget and looking for any suggestions or advice.With stock pistons? You'll be cutting alot off the deck, some pistons have been measured .120" down in the hole. Why not get some pistons with a taller compression height, then you can zero deck those pistons.
Ok, just wanted to clarify. Like MOPAROFFICIAL said, it's more about RPM that they will take. Factory rods and cranks are pretty good, but with the rods they might have to be resized, then you might want to upgrade the fasteners, so you're pretty close to a set of Scat I-beam rods which are really good for the money.I do plan on getting pistons, just wondering what the stock crank and rods will handle. Trying to get the most out of it on a small budget and looking for any suggestions or advice.
I will check out the Scat I- beams, thanks for the info RammerJammer75Ok, just wanted to clarify. Like MOPAROFFICIAL said, it's more about RPM that they will take. Factory rods and cranks are pretty good, but with the rods they might have to be resized, then you might want to upgrade the fasteners, so you're pretty close to a set of Scat I-beam rods which are really good for the money.
This is all new to meThe higher the CR, the tighter the tuneup window. E85 is a bit more forgiving, but I wouldn’t use any more CR than you think you can tune.
This is all new to me as I've never had a high compression engine so I'm interested in what the difference is in tuning higher compressionThe higher the CR, the tighter the tuneup window. E85 is a bit more forgiving, but I wouldn’t use any more CR than you think you can tune.
I'm currently running 13:1 compression with my 408 on e85. The pistons are 5 thousands out of the hole with a 57cc Edelbrock head (ported). I also use Scat I-beams (great rod for the money). I have heard that you can go a little over 14:1 on e85...but I have no idea if you would have head gasket issues at that level (I'm using Felpro 1008's). My engine does seal up well with studs (also a good idea for high compression).
One thing you will need if you are going to run e85 is a wide-band O2 sensor. e85 burns so clean that it is VERY difficult to read plugs. The wide-band is about the only way to get a safe tune on the carb without guessing. I run my car between 0.77-0.82 lambda at WOT.
With that said, you can make pretty stupid power with the right setup....my Barracuda is running low 10's on e85 and can drive most anywhere...except past a gas station.
I'm currently running 13:1 compression with my 408 on e85. The pistons are 5 thousands out of the hole with a 57cc Edelbrock head (ported). I also use Scat I-beams (great rod for the money). I have heard that you can go a little over 14:1 on e85...but I have no idea if you would have head gasket issues at that level (I'm using Felpro 1008's). My engine does seal up well with studs (also a good idea for high compression).
One thing you will need if you are going to run e85 is a wide-band O2 sensor. e85 burns so clean that it is VERY difficult to read plugs. The wide-band is about the only way to get a safe tune on the carb without guessing. I run my car between 0.77-0.82 lambda at WOT.
With that said, you can make pretty stupid power with the right setup....my Barracuda is running low 10's on e85 and can drive most anywhere...except past a gas station.
I greatly appreciate the great information flyfish. I am definitely going to be going with the Scat I-beams and studs for the mains and heads. Looking hard at the KB 167 pistons and will definitely go with wide-band O2 sensors. What carburetor are you running? Again I greatly appreciate the helpful information.My small block race motor ran reliably with 13-1 on alky in a dirt modified.
Mopar 340 rods and a Mopar billet steel crank. Stock parts are tuff enough that its unlikely you will break either.
The issues you will have with HIGH RPM is with the oiling system. Get that right and you are golden.
I would have the mains line honed with studs just to make sure they're true.I greatly appreciate the great information flyfish. I am definitely going to be going with the Scat I-beams and studs for the mains and heads. Looking hard at the KB 167 pistons and will definitely go with wide-band O2 sensors. What carburetor are you running? Again I greatly appreciate the helpful information.
Thanks for the info Krooser, I will definitely research the oiling system.My small block race motor ran reliably with 13-1 on alky in a dirt modified.
Mopar 340 rods and a Mopar billet steel crank. Stock parts are tuff enough that its unlikely you will break either.
The issues you will have with HIGH RPM is with the oiling system. Get that right and you are golden.
Thanks RammerJammer75, I was planning on that as well.I would have the mains line honed with studs just to make sure they're true.
Thanks RammerJammer75, I was planning on that as well.
I am getting ready to start a 318 build and would like to know how much compression a stock bottom end can handle and how much is achievable. It will be running on E 85 and will be race only.
My carb is a something I pieced together from ~ 4 old carbs... it's a bit "Frankensteined" carb....The important parts are a 750 Proform main and an e85 conversion kit I got off ebay from Rob Mix. After a whole lot of tuning, it is the one that stays on my 408 because it is fast and consistent. I also have a new Holley 950XP carb that is ~ 0.5mph faster, but it is unreliable for a foot brake racer like me. It has an occasional hesitation at the hit of the throttle that has cost me a few races...now it sits on a shelf for when I switch to leaving off a button.I greatly appreciate the great information flyfish. I am definitely going to be going with the Scat I-beams and studs for the mains and heads. Looking hard at the KB 167 pistons and will definitely go with wide-band O2 sensors. What carburetor are you running? Again I greatly appreciate the helpful information.