Thread: 350 engine components help!!!!

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Three years ago i purchased a rebuild 350 from high-performance-engines.com with the following:

9.1 to 1 compression
Valves- Intake 1.940" and Exhaust 1.500"
Cam- Lift intake and exhaust .417" hydraulic,
Duration intake and exhaust 247 degrees
Crankshaft: Cast nodular 3.48" stroke

Note: only has about 12,000 mile on it now. Also i have ford 9' 3.70 posi.

I have put on summit intake, holly 750 carb, and headers. Motor has approximatly 240 hp. What can I put in that will boost hp and torque. I have thought about changing the cam, i just dont know to what. When it comes to values and rockers not sure where to go from there. I would like not to have to change the pistons or the rods. I am looking not to spend lost of money, sorry in college! I have plans to put in an electric fan to help free up some power. Hope all the info is helpful, i am just looking for some direction form the "professionals." Thanks for the help!!!

chevyfan

1st- swap out that 750 cfm carb, it's too much. 600 will work better with your combo. Then get a cheater plate NoS system for it & your good.

I know that carb is to big. I have a 650 edlb. but it pisses me off so this was the alternative. Not to sure about NoS. After looking round for a while i think that my only option is to get a different cam. I am not sure if the one i have is considered good or not.

What cam can i go to without doing anything to the springs and rocker arms?

thanks

With the 750 you're probably washing you cylinder walls down with gas. For that engine, a 500 cfm would do just fine. A 600 would also work, but still more than you need.

My 350 has 10.5:1 compression, 2.02 fuelie heads, a Torker I intake, sanderson headers, crane cam and pumps out 350 hp using a 600 cfm. So I would doubt that you would need a 750.

I have several jets for the holly. If decrease the jet size will that help?.

Actually, if you decrease the jet size, you'll lean your mixture out. With that much carb on so little HP and rpm, your airspeed(velocity) is so low that you need bigger jets than what is considered normal to move sufficient fuel. Alternatively, you could put a good size cam in there to make more rpm's and HP to use a carb that big. Be sure to check your clearances and springs before you slide stick.

What heads do you have on it? Lots of horsepower per dollar spent for good heads..... Cam size, carb size doesn't really do much without good flowing heads......

Dave is right of course. I thought I read something about him being bucks down and heads are not cheap.

After doing some checking around i was refered to crane cam #113522 .050 duration I= 218 E=230, Lift I=.459 E=.486 with #11308-1 for springs. The head that are on i am assuming are just stock so 76 or 72cc. Also, i am going to get some 1.5 roller rockers. I had also thought of putting a electric fan on to free up some hp, are these ideas good or not?????? thanks

IMO, that might be a little much cam for stock heads. If you're going to spend the money on rollers, you might as well get 1.6's if there's room. Otherwise there is little benefit. You could also try the old trick of changing the rear gears for more acceleration without touching the motor at all.

well that was the cam suggested by the crane cam tech line. i hope it will work. If i am assuming that i have about 270hp what kinda of change will the cam make to the hp. Or any increase in cam, what is the benifit in general? If i increase the rockers then that is just like increasing my cam correct? i have 3.70's in the rear! thanks

really a big cam for a street engine is a waste of money if your looking for low end power, under 4- 4,500 RPM or so, as the cam gets bigger, you will make more HP but you will have to wind it up to get the extra power, and you will have less on the low end. by my calculations adding a single plane manifold will give you about 5 horse @ 4,000 but you will loose 3 horse in every rpm band below that. coming out to 252 HP @ 4000 using a simple .442 lift cam, you have 247 HP @ 4,000 now.

ehem.... as others have suggested... heads would really be a good way to go especially if you want to benefit from a bigger cam..... some AFRs will run you around $1100-1300 but you will really notice an increase.... a recent article from hmmm i forget where i saw i'm sure some others saw it, but they took a stock ford 5.0, put afr 165 heads on it, an intake, carb, and headers and got it to about 425 hp

Really quick, HP is a mathematical product of torque and rpm's. Your motor makes "x" torque. The more rpm's at which this "x" torque is made, the more HP. To make rpm's means supplying more air, hence, long duration cams-bigger valves-better flowing heads-bigger intake&carb etc. A bigger cam without a corresponding increase in flow capacity will produce only a marginal benefit. 3.73 gears are good, and 1.6 rockers will act like more cam. You could get the 1.6 rockers to crutch your existing cam until you come up with a more encompassing gameplan.

Originally Posted by cutlass389

Really quick, HP is a mathematical product of torque and rpm's. Your motor makes "x" torque. The more rpm's at which this "x" torque is made, the more HP. To make rpm's means supplying more air, hence, long duration cams-bigger valves-better flowing heads-bigger intake&carb etc. A bigger cam without a corresponding increase in flow capacity will produce only a marginal benefit. 3.73 gears are good, and 1.6 rockers will act like more cam. You could get the 1.6 rockers to crutch your existing cam until you come up with a more encompassing gameplan.

and because of this HP and Torque are the same at 5,250 RPM no matter what engine