Cam? what size is best.

[clarkaw1]

I'm rebuilding my 76 302, it has a C4 w/stock torque converter. I would like to go with a bigger cam for two reasons, more HP and more torque. The engine and heads will be stock with the thought of next year adding aluminum heads. Everything I read about bigger cam's with stock motors scares me because everybody wants the thump sound but "go to big and you will turn your motor into a turd". So what sizes do you guys recommend. My
budget consist of ~$1500.00 but I still have to block & heads to pay for ~$500. That's not including added bigger springs if needed. Besides that can some one please in laymen's terms explain how the cam effects the torque converter.

As a side note, it's freaky costly to go fast!

 

[broncnaz]

Thats a loaded question. but in short a lot of people use cams like the edelbrock performer or cams with similar specs. basically the camshaft affects where your power is made if the cam is to big the power is made to high in the RPM range to be useable, along those lines thats where higher stall torque converters are needed as the RPM's needed to make the torque required to move the vehicle is higher. Of course lower axle gearing is also needed when the cam is to large.
Its normally besst to pick a cam based upon your gearing and driving needs. Call a few cam company's they should give you some good suggestions as well based upon your vehicle specs.
Dont get me worng here but aluminum heads probably wont gain you much. Good flowing heads do make gains but really only in the upper RPM range. I put good heads on my 73 mostly because my stock ones where jacked up. still I didnt see any big gains in the lower RPM's. Stock heads are good for the engines we tend to run as stockers usually top out at 300 hp before they need work or better heads.
But by all means if you want the aluminum heads for for them I like mine.. Of course that budget may go out the window.

 

[clarkaw1]

Sorry for the loaded question but I liked your answer and I will call around tomorrow. Thanks

 

[airbur]

Call Scott at Cam Research.

http://www.camresearchcorp.com

 

[00gyrhed]

you really need to build the whole engine as a package. But basically lift and short duration = low end torque. lift + long duration and lots of overlap = low RPM turd - fast WOT.

you can go to summits website search comp cams and pick one that makes power from IDLE to no more than 5500 RPM. Unless you drive over 5500 rpm alot. That will actually be the lowest RPM power range they offer. Unless maybe they have an idle to 5000. Which you would probably like as well.


The more lift in that rpm range will make more low end torque. Unfortunately lots of lift in a flat tappet motor = short cam life, so your lift options will be limited as compared to a roller cam.

be wary of anyone appling WOT mistang go fast tdeas to you off road/street engine. Sometimes they tend to forget you will not likely operate your engine at wide open throttle much if at all, what you want is good throttle response, and easy transitions.

Basically if you spend money to make it breath better and you never need WOT. You spent too much money. On the other hand short duraion, low overlap, high lift cams are just safe bets to increase low end torque no matter what else you do to the engine. Even engines with great big intake runners and large intake valves will like the change. Its just that you dont always need to go there with that cam.

Try the cam and save your money for heads intake etc until you can change the bottomn end as well. Aluminum heads will allow you to run higher compression ratios, not to say bolting a set of aluminum heads on to you stock 302 wont help low rpm a little with a good RV type cam but it probably isnt worth the money and probably wont even be noticed until at or near WOT anyway.

If you get the thump thump you bought the wrong cam unless all you want to do is parade arround and show off. if you intend to use it off road you want something that idles dead smooth.

You will not have any issues with a stock TC if you stick with a cam in that range.

If you want to go cheap I would find a set of E7 heads on craigstlist locally. The nustang guys pull them off and give them away. You can often find good runable heads for $50. I actually have a set with 10K miles on them but they aint worth shipping to MI from TX. I would want more to box them up than they are worth.

They have hardened seats and good exhaust valves. That much less to pay for and if you cut out the thermactor hump with a fie grinder they will flow better than your stock heads.

 

[broncnaz]

I've had way better results with cams that make there power from about 1200-1600 RPM on up. you get better midrange with that type which is generally where you cruise at hiway speed. transmission and axle gearing take care of the off idle stuff.

 

[matts460]

Hmm stock heads means stock springs= Mild cam sir. Just need somthing in the idle-4800rpm range would be perfect match for an edlbrock Performer Intake (dual plane) manifold. Crane makes a very nice cams in this range (my perfered brand) Make nice low end power and keep vacuum for power brakes etc.. Also a small cam with good alum heads work better than stock cast heads with to large a cam. Mostly alum heads shave wheight and allow higher compression ratios with no detitation. Higher compressoin ratio means better milage and engine is much more effecient making power. Good luck man! Have fun! Somtimes its nice to have a "CAM" but has no lopey idle! Very very sneaky LOL

 

[broncnaz]

A higher Compression ratio doesnt mean more mileage. more power maybe even then its not much what ever compression ratio the camshaft calls for is what you want they usually have a range they work best with. most of the cams used in broncos are fine for the stock or slightly higher comp ratios. basically I'd shoot for a 9-1 comp ratio go to high and to small of a cam and you'll need premium fuel.

 

[bigjhoov]

I've heard of people having good results with a stock 351 cam in the 302. E303 seems pretty popular too.

 

[TwoDalesDad]

Be carefull when throwing new aluminum heads on a tired lower end. I have seen several engines granade due to the NeW ToP EnD. If you want it to run better start with headers, open exhaust, 4Barrel intake, and a performance Distributor. When you open the hood on an Early Bronco.....Open Your Wallet as well....Dont forget the essentials, high flow watet pump, high volume oil pump as well, and don't forget the timing set as well. GOOD LUCK AND HAVE FUN! !

 

[76 bronco J]

I've heard of people having good results with a stock 351 cam in the 302. E303 seems pretty popular too.

>> I just swaped out my E303 cam for the F4TE cam aka. explorer/351W roller cam.... believe that roller cam was for '94-'96 truck 5.0's / '94-'97 351W's & the '96-'01 5.0 explorers....... think lots of people ended up with the E cam 'cause Ford really misrepresented the cam for several years....the E cam really sucks with a stock auto convertor & a inefficent higher stall convertor is not a option for me....don't know how or why I dealt with it for 8 plus years & 20 something thousand miles....I detuned my 315hp. rated Y303 head/E303 cam crate engine that I bought back in 2004ish....engine still feels really strong & pulls to 5,000 rpms.....best idle for the E303 cam was 15in.'s of vacuum at 900 rpms with a ton of intial advance.... then when put in gear your floppin' around 10-12.....the F4TE/explorer/351 cam pulls 20in. of vacuum & 18in. in gear while idling smooth a silk...the engine is so much more truck like now again ,but will still go way faster than I should probably be pushing a early bronco.... check out the pics below...managed to swap the cam out without removing the intake using magnets & carriage bolts method....actually have the Anderson Tappet Tool set 'cause it was cheap used or I would have made a set for what they want.......

 

[rguest3]

Build any engine as a package so all the parts are compatible with each other.

I have had great success with Comp Cams. Get a "K-kit" which has the Cam, Lifters, Timing Chain, Springs and all the correct valve-train for your application. I recommend either the XE256H, or the XE262H Cams. Each one has a corresponding K-Kit as well. Maybe even add the Comp Cams Magnum Roller Tip Rockers. Stock heads will do fine as well, but they will need to be cleaned up before all valvetrain is installed.

Install the Edelbrock Performer 289 Intake and a 470-600 cfm carb. Headers will also help and let the rest breathe.


76Bronco J - Was your E-Cam advanced 4' when installed? Would make a difference in a Bronco. Ford Cams do not have a "built In" advance as most others do. I have an E-Cam (4' advance) in a 351w and it has VERY good low end torque.

 

[matts460]

Good solid compressoin ratio goes along way toward volumetric efficincy. with alum heads you can typically get away with higher compression ratios on 91 octane and not have problems with detonation. (within reason) Also you can have highish compression ratio with stock cam.

 

[76 bronco J]

76bronco j - was your e-cam advanced 4' when installed? Would make a difference in a bronco. Ford cams do not have a "built in" advance as most others do. I have an e-cam (4' advance) in a 351w and it has very good low end torque.

>>> it was installed straight up.....I imagine the with the E cam installed advanced along with the extra cubic inches does makes it behave different....I did have decent low end along with great throttle reponse with all the intial advance I was running & little 30x9.50 tires.... played with the timing alot since I was running a Crane digital distributor with the E cam....that 110 degree lobe seperation of the E303 cam seems to be the biggest issue for it idling like it's bigger than it is.... my older Y303 aluminum heads only have 160cc intake runners vs. 178cc. like the newer X heads & seem to work great with the F4TE cam.....for those with the newer(or should I say rebuilt, no more new ones) 5.0-X head crate engines a stock mustang 5.0 HO cam would idle way better than the E303 cam with just a slight loss on the upper end..... even many pushrod 5.0 mustang guys have finally figured out through the years a stock mustang HO cam with decent not too huge heads/intake makes a really great drivable combination.....then you add boost for more power if needed without screwing up any of the driveability.....

 

[rguest3]

I also have the GT-40X (178cc) heads with the E-Cam installed on the 351w. Correct, 110 Lobe separation is better with carb as mine is. 600cfm carb and RPM intake are a Great combo in my book.

Extra cubes with the 351W eats up some of the E-Cam (220, 220) duration, may be too much in a 5.0 in a Bronco.

 

[Broncobowsher]

Good solid compressoin ratio goes along way toward volumetric efficincy. with alum heads you can typically get away with higher compression ratios on 91 octane and not have problems with detonation. (within reason) Also you can have highish compression ratio with stock cam.

Thermal efficincy. Real simply, you get more pop per drop (of fuel)
Volumetric efficincy is simply moving the air through the engine and has more to do with runner shape, valve timing, etc.
More compression is better, so long as you have the fuel (octane) so support it.

This gets into a whole new chapter, cylinder pressures. Increasing compression ratio is a very obvious way to increase cylinder pressure. But valve timing has a lot to do with it as well. The huge compression ratio numbers in high HP engines is also backed by big lumpy cams that don't close the valves in time to build optimal cylinder pressures, especially at low engine speeds. But they make up for that by making good volumetric efficincy at higher RPMs. Velocity, momentium, will let the engine keep making power at higher RPMs then a stock cam would.
An RV style cam plays with the valve timing a little to bolster the cylinder pressures notibly at low RPMs. Add in a little extra valve lift to promote better flow and you have the classic RV cam that wakes up a stock engine.
If you go a step further look at diesel cams. They are there to maximize cylinder pressures so you have enough compression to light off the diesel fuel. If you were to take a 14:1 compression engine you are talking a low compression diesel or a high compression gas engine. The difference is how the cam is profiled. With a gas engine lots of overlap, long drawn out valve timing to keep the cylinder pressures in check. But a diesel will need the intake to close very near BDC just so there will be enough cylinder pressure to light off the fuel. All in the valve timing.

The last 351 I built turning into an 11:1 aluminum headed beast. I was aiming for high 9's but didn't correctly factor in the short deck height of the '70 block. I already had the RV style cam. That chased my cranking compression into the 200+ PSI range. It was sensitive to timing, a little too much and it rattled. On a hot day and the water temp went past 200° and it would like to rattle. On a hot restart it would start as a diesel, my rattle start. I am sure the only way it lived as good as it did was all the little tricks I put into the engine as I built it. Chamfered all the sharp edges in the head, especially around the plugs. Ceramic coated the piston face. (accidently) ran a super tight quench height. Not a way you should plan to build an engine, but it happen to work out and run real good.

Compression is great for making an engine run good, just not too much.

 

[clarkaw1]

I want to say Thank You to everyone that posted a reply. I'm a little late with my reply's and I do apologize for it. I have had the most stressful two weeks. My Mother was Diagnosed with a brain aneurysm and then this past Monday my Father in-law had a massive stroke. My Mother looks like she's going to be Okay. My Father in-law not some much ?:? Thanks again for your help.

 

[Rickb1b]

Sorry to hear about your family.

I just bought an Edelbrock Performer intake, cam, lifters and timing chain for my 302, all brand new. I don't think I'm going to use them. I think I'm going to get a 351, my 302 is too worn out to handle this upgrade. If you want to save a few bucks PM me.