Opinions on camming a used engine. experiences, etc

I am preparing to pull my 427 and replace it with a 327. It is a typical used small block Chevy, good bearings and compression, sludge, etc. Just typical. The plan was to put a new, stock 350 cam and lifters in it, and go. Cam 2, is an old SSI(remember them) performance cam, with numbers very similar to the old 350 horse 327 cam. I've heard all the horror stories about taking an engine set in its ways, and upgrading its usage, broken piston rings, stretch, etc. I've run and blown my share of engines, new and used. This is the first time I've cared, and wanted it to survive. So what do ya'all think. Stock cam and lifters, stock with 1.6 rockers, or the 350 horse cam? I'm not an agressive driver anymore, but when I get into it, I bury it. All parts are on hand to do any of the above, so I'm not buying anything .

 

I would not waste a good cam in a wasted engine, but it sounds like your engine is not yet wasted. I doubt that you will screw it up with a healthier cam shaft that what it has.

 

The only thing I can imagine happening would be that, if you spin it a lot faster than is is used to, there may be enough stretch to make the rings hit any cylinder wall ridge harder than it has before, maybe cracking the top ring lands. Normally the RPM limit is due to valve float, so if the 327 has hit that float limit before, and you're not changing springs, you should be good in that department. Does "Cam 2" have more lift than what the existing springs will handle?

 

The question has no right answer. It doesn't look like you've personally run the 327", so you'll have no referent to determine if the cam change helped or hurt. If it dies, it might have been going out any way.

The one thing you didn't mention which is an absolute must is new valve springs matched to the cam. Installing a more aggressive cam on old, soft springs is a recipe for disaster.

jack vines

 

Cam 2 is .445 lift. , longer duration. engine is a stock 250 horse 327, with stock intake and carb(to be replaced with c4b/afb combo), so doubt it was redlined at all. My driving habits being what they are, I would be redlining it periodocally. I do love the sound of a 327 winding past 6,000 R.P.M., hence my quandry.

 

That's a fairly conservative cam so you should be okay. I'd still be careful about winding it up with the old valve springs though.

We used to buy used motors for our stock cars (we had no money..) and would change the cam & lifters and go racing. If we had some extra bucks, we went for exchange heads.

So while you have it apart think about "springing" for a valve job.

Bob

 

Sludge is not normal. I would consider, if the engine is on the stand, pull the pan, clean it, inspect the rear bearing since it takes the biggest stress when hammered.

If all checks out, and

If you have good compression, and its a low mileage engine. It may be an ideal candidate for a mild cam. The rest is easily broken in....

 

My experience of changing cam, intake, headers etc. on an old engine is that it blows sky high in a month or 2. While if you leave it alone and baby it, it may go for years.

If you want to do this on an unknown engine, either have a spare for when it blows up, or tear it down first, inspect ,and replace rings, bearings, timing chain etc. If cylinders and crankshaft are not too worn, you may get another 50,000 miles out of it.

 

I bought a rod that had a Good Wrench 350 and swapped cams to an XE262H. Worked out great with the stock springs, but didn't push it past 5500 rpm.

 

I used to wussy out on them old "running" 327's and quick tear down check bearings, at least 4, spend hours getting the sludge out, change cam and always found something questionable. My old man used to get pissed, said I was waisting time and money, "them old motors are tough and it was running good before". For the most part he was right. He would just change cam/ lift ers change oil/filter and go wind the nuts off them, some how they always stood up for him. I say a lot was he was just luckey that way. Any way, I started cheating to and have gotten away with it so far...


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The newest 327 is now over 40 years old. There is a difference between a 5 year old engine, a 10 year old engine, and a 40 year old engine.

 

A few years ago I put an Isky 30-30 in 400 sbc and never had any problems and the engine had over 80,000 on the clock