I have a 1979 chrysler 300. Right know it has -Stock heads ported and polished with heavy springs and 2.02intake/1.60 exhaust valvesEdelbrock performer intakeDemon sizzler built thermoquadRoller chaincomp cams extreme engery cam ADV. DURATION 276/286DURATION @ .050 230/236VALVE LIFT .488/.491LOBE CENTER 110Headers, 2.5 inch exhaust with x-pipe.727 trans with shift kit and mopar performance stall K175 I think with 3.55 gears sure grip. It seems to run pretty good but thinking about taking it part adn bumping up compression I think 9 to 9:5:1 would be good to wake it up some more. I know the intake the ports are a little smaller than the heads. SO what do y ou guys think what brand and type of pistion should I run to get what i need and what intake. Any info on my combination to make it better would be awssome to get this late B body moving a little better.
well it sounds to me like you have a great base that your starting with. what are you plaining on doing with the car. what type of power and rpms do you want to make? if it was me, stock comp ratio in a '79 360cid is 8.6:1, this can be uped by simply advancing the camshaft timing. this will alow for longer afective stroke increasing the cylinder pressures inturn increasing the comp ratio. but if you still want to change to pistons i would recomend at least 9.5:1 if not a 10.0:1 forged piston. Kieth black offers forged starting around $430. you could also run the hypereutectic's that start around $200. it is a better piston than the oem and only needs about .003" to .004" piston to wall clearance, where the forged require at least .005". but as always air flow is the key to performance. port matching your heads and intake could be a help but a good polish to the runners will help as well. i run the same intake on my 360cid small block and i felt it had adiquate air flow after i polished the runners smooth. i run a 10.0:1 comp ratio with a .501 lift cam. i think that with a little work that 360 will carry that b body just nice.
So how much should I advance the cam? Is it like 4 degrees or something since the crank gear on the timing chain has three spots or should I used a offset key. If I advance the cam timing will it still run good on bottom or top end or does it benifit one more than the other. Thanks for the info. IT seeems to run good know prob a 14-15 second car as heavy it is I could be way off though.
you cam timing will affect the rpm range that the engine will perform best. the more advance that it is that more torque you will have at low rpm. the more you retard the cam timing, the more high rpm top end hp you will have. ill have to do some math to figure exact numbers for you. but the idea of it is that the sooner the intake valve opens leting the air/fuel charge into the cylinder, then closing sooner alowing for a longer afective stroke, will intern create a higher cylender pressure/comp ratio. factory comp ratios though on 79/80 360's are at 8.6 to 9.1:1 anyway. but i will get some better numbers for you to be able to work with.
Thanks for the info. The rpm range is between 2000-5500 rpm is where it will see the most use thanks.
by the way the lift you listed was valve lift. do you by chance know the lobe lift. if not i can figure it out though the rocker arm ratio, more than likely 1.5:1 correct thanks
It is a 1:5 ratio comp cams roller rockers
sorry i didnt get back to you any sooner. i've been pretty busy with this darn snow we just got over the weekend. i have been working on an answer for you and i think i got it. for every 1 degree of cam timing you advance it from the strate up position the piston will be .019889" lower in the hole when the intake valve closes. so if it is already 4 degrees advance then the affective stroke will be .079556" longer. and if you add 5 more degrees with an offset key on the cam your affective stroke will be .179001" longer. i know that it dont sound like much but also know that for every 2 degrees that you advance your cam timing your power band will move 500 RPMs lower and vice a versa. so if your power band was at 2500-6500RPMs, with it advanced 4 degrees from there it will drop to 1500-5500RPMs witch is around what you want it at. the tune of the engine is related to how well it breaths, like always air flow is key so if your heads cant handle the air flow at 6000RPMs but almost peak at 5500RPMs then you can adjust the cam timing to match it.
thanks for the info. Mine is dot to dot right know. The heads are stock cast iron with a full port and polish with 2.02/1.60 valve with headers and 2.5 inch exhaust. So would it be better to advance it on the crank or cam. Or does it matter. I think the timing chain set i have you can advance it 4degrees or retard it 4 degrees on the crank. Have to look. So how much will that raise compression on a 8:5:1 or 9:0 360 motor?
Yeah i dont think the motor would like 6000 grand haha
well being that you have a crank gear that has 3 places on it i would use that as a base advancement. because the offset key works good but i have found that i only somewhat trust it being used in the cam not the crank. i messed up a good set of heads, valves and push rod useing the offset key in a crank one time, never again. the key striped off at around 3500-4000 RPMs wasnt pretty. the cam though has been fine no problem out of it so far. the multi degree crank gears i havent seen to many strip out but anything can happen. anyway the cam timing beging 4 degrees advance will bump your comp ratio roughly about .10 to .12 points. like i said it dosent sound like much but every little bit helps. but just changing the position of the gear isnt everything. to properly do it you should degree the engine. useing a dial indacator, degree wheel and other nessary tools to degree it will let you be able to compensate for chain slack, and other things.