I have a stock 1970 350 that was rebuilt to stock a few years ago. I want to put a mild cam in it to give it that lope sound at idle. Do I need to change the pushrods and springs to do this or just the cam and lifters? Anyone know a good cam that will get these results? Also, any secrets to intalling a cam? Thanks
If all you want is a bump , you can install something like a Crane "FireBall" cam. they use stock springs so the cost is low. $139.00 at Summit
option 1: 1.6 rocker arms They will take a .450" lift to a .480", .500 to .533. stock springs won't take much beyond a .500 unless they are "z-28" springs, so don't go nuts. option 2: reground cam, cheaper and available at your local parts store. may require longer pushrods to correct valvetrain geomety (esp important at higher rpm) option 3: new not reground (comp/ crane/ etc) If you do too much, it might mess with your converter if you run an automatic. go with a 1200-5500 cam use a long bolt to help install it, soak the new lifters in a oil bag overnight. use lots of break in lube with zinc.
You also dont want to go towards .500 lift without going to screw in studs. Stock press in studs will start to pull out causing anything from valve lash changes and water in the oil to catastrophic failure.
It sounds like you're just looking for an improved sound for circling the drive-in. Chevy still sells over the counter a 350horse cam for sbcs. It really works pretty good on the street and gives that nice lope. I've used it about 4 times. One time in a 307ci. I changed heads on the engine for a set of 350 heads with larger valves an Edelbrock with Holly carb and a set of budget headers. Made a very nice, well behaved street engine that beat the **** out of my buddy's 350 since he told me a 307 was junk. It's nice when a plan comes together.
Oh and I forgot the second part of your question. Use cam lub on the cam. Run the engine for a short time then change the oil and filter. What's a short time you ask. I forgot, but some of these guys know.
I run the 20 minutes (minimum) break-in then change the oil. If you run synthetic, break in with regular oil. Try to find SF oil also.
I run the engine for 20 minutes and keep alternating the engine speed from 2000-2500 RPM. Then as mentioned before drop the oil, and refill. Make sure your timing is set correctly to prevent damamge. I found that the Isky 270 Mega Cam was a good all around street cam. I would recommennd springs anyways, they aren't that expensive, and unless they are fairly new are probably worn anyways. They can also be replaced without removing the heads. Just charged the cylinders with air at TDC on the compression stroke. Good luck.
a stock motor will run like **** (lousy power at usable, street RPM's) with a cam that has numbers to produce a lopey idle. I wouldn't do it. I know it's tempting
put a 268 comp high energy in it...and use a break in additive. has a little lope and makes usable power where you need it. and doesn't require a looser convertor ...
Not so. The diesel oils R losing the Zinc also sometimes. I use Valvoline Racing Oil (20/50 from any Autozone/Pep Boys). Being an "off road" oil, it will not have the zinc removed. I'd also add a bottle of someone's zinc additive/cam break-in supplement.
I agree, it's the cam I'm running in my daily driver 350, great throttle response, strong bottom end and midrange, and a very mild lope. I installed it with the recommended CC lifters, springs, retainers and locks.
Something around 270 duration and 110 lobe separation should do what you want and not have so much lift that you have to replace springs. And you shouldn't have to get a stall if you're running an automatic. Good luck
SUMMIT RACING has some very inexpensive cams that get good reviews. You can get a kit with springs, seals, locks, lifters, and push rods cheaper than most will sell the cam for. By all means, change that cam if you have a chance. Measure and do the math on the lift of your stock cam. You may be surprised at how little lift it provides and even the smallest performance cam will be a huge improvement.
I agree here. The lobe separation angle (LSA) is what really has an effect for the lopey idle when the cam is smaller duration. 110 or less will have more lopey sound than greater than 110 LSA, all else being equal. Smaller LSA also gives less idle vacuum. When your engine was rebuiolt a few years ago, as you stated, did it get new valve springs? If so, you can probably get by with them if you keep the lift below .480 total. If you don;t know, new springs are cheap and you can get .500 or .550 lift springs that fit the stock spring pockets for cheap. The generic "Z28 springs" are the .550 lift capacity. The Comp Cams 268 is a good street cam for daily driver and will work great with stock springs, but I believe it has LSA around 112 or 114. The choices are almost endless from many of the cam mfrs. Use duration at .050 to be 220-230 and LSA at 110 or less and you will get the lope you want without excessive lift. This should also be OK for stock converter.
Quote: <TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD cl***=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by brandon put a 268 comp high energy in it...and use a break in additive. has a little lope and makes usable power where you need it. and doesn't require a looser convertor ... </TD></TR></TBODY></TABLE> This is a great cam, I've used it in 283, 307 ,350 and a 383. It is a great all around cam. If you're looking for something really lopey, this is probably not the cam for you. Understand that when you go much bigger than the 268 that all the other items mentioned start to come into play to make the cam effective. Headers will make a big difference in performance on the bigger cams as well.
While its true that the Factory Z/28 springs will work great with this cam, a lot of aftermarket springs in the .550 range will have a lot more seat and open pressure which might cause problems when relying on press in rocker studs. Tell them exactly what you have before ordering. I run a Blue Racer cam by Wolverine (sub-division of Crane, Im told) in one of my 350's, which has very close specs to the Comp 268 but I believe it has a 110 LSA...works great with a stock converter, is very responsive off idle, but has a nice lope. I remember the duration @.050 was 218/221 and the lift was just under .480. I ran a cam with 230 duration @.050 and 110 LSA in an otherwise stock 350 and it wasnt at its best with a stock converter and the lack of low speed torque made drivability suffer a bit.
do I need a degree tool for installing the cam? I have an edelbrock performer intake and carb for it and was leaning towards the edelbrock camshaft, but nobody even mentioned them. is there a reason for that? thanks
Be sure to keep the intake duration in the 220 degree or less range, you can go 225 or so on the exhaust which will actually help fill the cylinder for the intake cycle. Do not get caught up in getting the most lift you can, .480-.490 intake & exhaust is plenty. Install hardened locks and you can use the stock chevy retainers (NO ROTATORS) which work work great & stand up up to higher spring pressure. The TRW P/N for the Z-28 springs used to be VS1008, there are a ton of equivalent springs that work very well. If you have flat top pistons & 76 cc heads with Fel Pro gaskets (.038 thick) or the equivalent it will be just creeping into the 9.25-9.5:1 compression ratio so a big cam will kill your low speed power. If you just want to plug the cam in and do not have a setup to degree it there is a pretty easy way to get good performance with a low compression motor. First find your baseline cranking compression with the new cam installed. Get a set of cam degree bushings and install one (I think a 23/32 drill is what you use on the cam sprocket) and advance the cam (you will be moving the sprocket back to move the cam forward!!!). Check the compression again and see if it went up. Keep advancing until you get the highest reading and you now have the highest cylinder pressure which will give you the best low end torque. If you use a timing chain set which can be adjusted with lock screws etc then it is even easier. You can do this with only 1 cylinder set up with pushrods & lifters which will let the engine spin faster and keep you cam & lifters from getting torn up. Remember, if you advance the cam you move the powerband down so it will take some power from the top. With what you in the motor have the max RPM should be no more than 5,500 anyway and your engine will love you if you keep it well below that!!!. High RPM's like to jack studs out of heads and squeak the front 2 rod bearings.
Look in Jegs line of cams , the 442/465 lift can 214/224* dur @.050 works great for a street cam , little idle good broad midrange power , stock springs and converter work with it . I'd ditch the perfromer and go for a torker, holley street dominator performer RPM . thats me though . To answer the why not edlebrock cams ? Its the same clevite cam sold by Jegs, Pro Gear, Wolverine , Elgin , sealed power etc. buy in fancy box with a sticker for more money . we refer to these as generic cams. Not max power cams but better than stock and low cost, perfect for tiawanna rebuilds
Those specs are actually for the Comp Extreme Energy 268 camshaft. I may be aging myself, but Im pretty sure everybody is talking about the older Comp High Energy grind which is a bit more tame: .454 int/exh lift, 218 int/exh duration @.050 and 268 advertised duration. Id also suggest staying with a dual plane intake like the performer, Torkers and Strip Dominators are single plane intakes, generally for higher RPM use, so you will lose a lot of low end throttle response.
what about those single plain intakes with the removable plenum divider if you run the divider it would now become a true dualplane intake?
I agree with the 268 hyd cams - good choice. I have a Comp XE 268H in my 355 - sounds great & good power (9.5:1, dual plane & Qjet). Lunati Voodoo 268 looks good too. Regardless of the cam you decide on, make sure you get good lifters. Most of the cam kits come with cheap lifters. There's only a couple of US made lifters, & Johnson is one of them. Here's a link http://www.sec-llc.com
I had a used Offenhauser intake like that. There were supposed to be a couple different dividers for different rpm ranges. Mine didnt have any of the dividers so Im not sure how well they worked. I dont think it did much more than move the port openings up changing the volume of the plenum...it wouldnt make it a "true dual plane".
Weind 7546 , great intake but not be a "true dual plane" split plenum I think would be proper way to describe it. Works great , used one with divider and a manly 480 lift cam , no stall no gears and car ran well ,
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