Thread: 350 Questions?????

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After all these months! I finally ordered my engine kit today and have coming with it a 223/223-447/447 camshaft. This is a standard bore 350 4 bolt main with 993 heads. I am trying to achive a 350/350 hp plant. I still need to order carb, intake and what the heck, I will get a new distibutor while I'm at it. Any suggestions on rockers, intake& carb? Any other positive posts will be appreciated.

Many Thanks!

You should have zeroed in on the static compression ratio before choosing the cam.

Also, stock heads are a little lazy on the exhaust side, so most fellows will order a dual-pattern cam that has a little more duration and lift on the exhaust side. You can also use a single pattern cam with 1.5 rockers on the intake and 1.6 rockers on the exhaust. It's not something that will make a world-beater out of a street motor, but every little bit helps the combination. Be sure to closely check for valve spring coil bind, retainer to guide boss interference, binding of the rocker on the stud and valve to piston clearance.

Generally speaking, a dual plane 180 degree manifold such as a Edelbrock Performer will do a good job on a street motor with a fairly mild cam. If camming the motor for higher rpm's, a Performer RPM or an Air Gap RPM might be a better choice. If a street-strip motor with a loose converter and a ton of cam, a Victor Jr. or other single-plane manifold might be a better choice.

Up to about 5,500 rpm's, a 350 with Chevy heads won't need more than about 600 cfm of carburetor.

I appreciate your responce, but help me out a little on the reply. When I posted earlier several months ago, posters were saying go with a 484 lift cam.

Thanks!

I bought this cam locally. So your advise to this cam size would be?

Many thanks!

compression ratio, you really need it when picking cams, they all have a compression ratio that they are supposto run at, light cams and some mild cams you do not need to worry about as they don't take much compression to run them correctly. basicly figure out your comp ratio, then buy the hottest cam you can for that comp ratio

My pistons are Sealed Power 345np flat tops.. The heads are 993 or 76cc. How would this 223/223/ 447/447 cam match up?

Thanks

OK. I am going to build the short block this weekend. If any more positive posts can be submitted, I will appreciate any. I Have the following:

350 Standard bore
993/76cc heads
223/223 447/447 cam shaft
Sealed Power 345np Flat tops

Will this combination work?? I am not planning on driving this machine east to west coast. Just a weekend cruiser. Any suggestions on different heads cams???

Many thanks!

64cc heads will work better. also, do you have the pistions yet, if not like a .100 dome piston would compensate for the most part with gaining higher the compression, higher compression will make the cam work to it's full potential.

That cam is designed to operate with a compression ratio of between 9.50:1 and 10.75:1.

Your compression ratio with 0.030" deck height will be 8.38:1, with zero deck and a 0.039" gasket, 8.86:1.

Either lighten up on the cam or tighten up on the compression ratio. Otherwise, you'll have a mis-match of parts.

Thanks for all of the positive posts. Now knowing what I have and still want to acheive the 350hp/350ci, what would be your best objective? Although money is trying to be saved, I will spend some money on these heads, or will pursue a different set. I don't and will not put a bunch of mis-matched parts in this engine. I have built three engines in my life, but have always gone back stock. I can trade in the cam, shave the heads, or get different ones.


Many thanks!

Wow, what a place to start. Everything fresh and the quest of 1hp per cube.
Essentially, the cam is the heart of the engine. The rest is what the cam sends blood to.
With fuel the way it is going to go, I would stay low compression.
An Edelbrock EGR 600CFM carb makes my 350 purr. It is almost a stock rebuild in terms of pistons, valve and porting set up. The cam is Summit SUM1101. That is a .196/.224. After chasing multiple vaccum leaks, and changing the bottom spacer to a four hole spacer, it ran without hesitation, hitting the accelerator was a linear acceleration. Good fuel mileage, gobs of torque.
When I do it again, I would put a quick change timing cover, open up the pushrod channels for 1.6 rockers. Then I would play after the fact.
Mind you, with the SUM1101 camshaft, the engine idles with very little lope. The exhaust tone at idle is distinct hits for each exhaust cycle. With a 2.73 rear, I get reliable 19-22mpg in my van. I can also leave most vehicles in my rear view mirror from a light. This is all at much less than WOT!
I use the performer manifold, HEI ignition. Because I am not removing my heads at this time, I am going with 1.5 roller tip rockers.
A van is much different to change heads than something with an hood. Much more logistics with half the engine in front, and half in the dashboard.
My exhaust manifold is stock, except, I am a gem cutter. I got some drag line cable, injected grit and polished the inside of the manifold through each runner. I do not know if that helped anything except make me feel good as I have no baseline to compare. Headers in my rig is not really a concern. Too much heat. I run 2.5" pipes down each side with a 2.5 Siamese Crossover, I also run the mufflers just behind the manifolds.
Doing it over? I would go with full roller cam, with full roller rockers. Less mass friction. I would also swap out the Edelbrock for a TBI rig, even if I did not have a computer on board.
I have found, some rad is really cool. For a while. Gads, I almost sound like a fuddy duddy, but, I had one of those once, and it got real old real quick. My friends really liked my rig, but, they went out and had fun, and I had to tweak the parts. My van is still not really finished on the outside, but, I get more thumbs up from the rodders here at lights than I ever used to. Mind you, I druel at their rigs. Some are really fantastic.
As a matter of fact, next time I do a build, before I really start, I am going to fly against some of these long timers on this board first, they really take the time to put figuires up that really make sense. I could have saved some pocket change if I had found this board before I started.
Good building. I bet it is going to purr when you are done.

Give Edelbrock tech line a call at 1 800 416 8628 they can give you an entire package, they can match all the components to give you 425 hp. Cam, intake, heads and carb. Just tell them what you got and where you want to get to and they will tell you what parts to get.

Give Edelbrock tech line a call at 1 800 416 8628 they can give you an entire package, they can match all the components to give you 425 hp. Cam, intake, heads and carb. Just tell them what you got and where you want to get to and they will tell you what parts to get.