351M build up
#1
08-09-2004, 08:10 PM
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351M build up
I am a tractor puller and we have a automotive engine class. I want to build a 351M into a real torque monster under a $1500 budget. here are the rules
small Block( we consider cleveland and Modified a small block)
OEM cast iron block and heads
6500 RPMS
1 carb 1050CFM max
365 CID
no nitrous,or any additives or pressure on fuel tank
gasoline or racing fuel.
I would like to use cleveland heads. i want at least 400 plus lbs torque and at least 325 hp. I can go to $2000 budget. I need some help
small Block( we consider cleveland and Modified a small block)
OEM cast iron block and heads
6500 RPMS
1 carb 1050CFM max
365 CID
no nitrous,or any additives or pressure on fuel tank
gasoline or racing fuel.
I would like to use cleveland heads. i want at least 400 plus lbs torque and at least 325 hp. I can go to $2000 budget. I need some help
#2
08-10-2004, 02:58 PM
why run the 351m, you have a CI restriction or I would suggest BBF or the 400, but with that I would really consider the 351C instead it is lighter, and has alot more intake manifold, and piston choices with the same bore, and stroke, with the only advantage of the 351m being longer rods which really isn't going to help you.
for building that first thing I noticed is you can run race gas (or 100LL I assume) then consider a set of Aussie 2v heads these will jump the compression up considerably without using pop up pistons which can inhibit the flame front causing, an incomplete burn, plus they will have a quench which will allow for more timing with the same compression, and fuel, I realize it adds alittle to the price but would be worth it in your case. I defenitly stay away from 4v heads as they will hurt your low end torque they can be made to run great but are really a High rpm head.
Next stay away from big tube headers I suggest 1-3/4 max primary with atleast a 18" collector. Next even though you can run upto 1000+cfm don't run more than 670 a 650 would be better (unless you run a predator carb) you don't need more cfm than that below 6500rpm.
next is the cam try, and get one with atleast 110deg LSA (112 would be better)this will widen out your torque band (it will lower your peak hp, but increase your torque for a wider rpm range) keep your duration below 230@.050, (228exh, 222int would work pretty good) I would say roller but that will greatly hurt the pocket book, but definatly go with solid, and yes you will hae to install studs, and guide plates in the heads for adjustable valve train
for building that first thing I noticed is you can run race gas (or 100LL I assume) then consider a set of Aussie 2v heads these will jump the compression up considerably without using pop up pistons which can inhibit the flame front causing, an incomplete burn, plus they will have a quench which will allow for more timing with the same compression, and fuel, I realize it adds alittle to the price but would be worth it in your case. I defenitly stay away from 4v heads as they will hurt your low end torque they can be made to run great but are really a High rpm head.
Next stay away from big tube headers I suggest 1-3/4 max primary with atleast a 18" collector. Next even though you can run upto 1000+cfm don't run more than 670 a 650 would be better (unless you run a predator carb) you don't need more cfm than that below 6500rpm.
next is the cam try, and get one with atleast 110deg LSA (112 would be better)this will widen out your torque band (it will lower your peak hp, but increase your torque for a wider rpm range) keep your duration below 230@.050, (228exh, 222int would work pretty good) I would say roller but that will greatly hurt the pocket book, but definatly go with solid, and yes you will hae to install studs, and guide plates in the heads for adjustable valve train
#3
08-10-2004, 09:14 PM
365 cid ??? thats why the 351m and not a 400 huh ... aussie heads for sure, but i'm not going to say alot else other than some food for thought.
Rules call for a small block right? I don't know if tractor pulling is anything like mud racing but our 351m and 400m were considered small blocks for 2 seasons.... after that the cry babies that were not finishing in the money with their 302's and sb chev's started crying about M's really being a big block. Enough crying and the M's got tossed in with the big block classes. ( other than street leagl )
Only you can say for sure, but if you could be looking at a rules change from the "cry baby factor" you may consider using a true sb 351w from the start.
Rules call for a small block right? I don't know if tractor pulling is anything like mud racing but our 351m and 400m were considered small blocks for 2 seasons.... after that the cry babies that were not finishing in the money with their 302's and sb chev's started crying about M's really being a big block. Enough crying and the M's got tossed in with the big block classes. ( other than street leagl )
Only you can say for sure, but if you could be looking at a rules change from the "cry baby factor" you may consider using a true sb 351w from the start.
#4
08-21-2004, 12:50 AM
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ok ported 351m/400 shaved will do nicely(you said racing fuel is OK?) heads ..
after running it thru the compression calc think closed chamber are infact needed
check and hard block the well block punch it 60 over will get 362.493 cubes
how "stock or OEM" must it be?
roller cam? solid lifters?
after running it thru the compression calc think closed chamber are infact needed
check and hard block the well block punch it 60 over will get 362.493 cubes
how "stock or OEM" must it be?
roller cam? solid lifters?
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