Thread: 350 build bottleneck???

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What's the static compression ratio? What are the specs on the cam?
You'll pick up around 30 hp with a high-rise, dual-plane intake such as a Performer RPM.

I'm sorry, but this reads like a magazine rebuild. First, what is the intended use of the engine? 4/7 cam swaps have NO value in street driven engines. Any benefit they show is usually above 7000 RPM.
What is the compression ratio, as a guess, I'd put it at about 8-1 UGH!!

\What is the duration of the cam?? It appears to be WAY TOO MUCH CAM for an 8-1 motor. Is this a street driver, street/strip or strip only car??

I wouldn't do ANYTHING until these basic questions and needs were addressed.

I have built many motors of all different sizes, and have never killed a cam !! and after reading all this crap. I'm confused! To much about nothing

I use farm tractor or Diesel grade oil, it has zink in it, there are others also, I use to break in my motors, (1st 3-500 miles on a street motor) then you can switch to synthetic. And use light valve springs & stock rockers till the cam & lifters are broke in.

Google flat tappet breakin and you'll find many more oils to use, and a lot better info!!!!!!!

Pat

Originally Posted by techinspector1

What's the static compression ratio? What are the specs on the cam?
You'll pick up around 30 hp with a high-rise, dual-plane intake such as a Performer RPM.

I know it's a lower duration cam I gotta call the company to get the specs again. I wanna say in the mid 230s on each but I'm just pulling that outta the air... How bout just a spacer on my current dual plane performer intake? It's hard to find spreadbore performance intakes used and I'm on a budget... I'm not 100% but I think the compression even with flat tops is only in the high 8's. Should I get domes? I bought everything but the rebuild kit so pistons can still be changed.

kejross, you're no different than thousands of other newbies who purchase a cam for their rebuild without knowing the static compression ratio, much less the dynamic compression ratio of their motor. You need to get some books and do some reading. You have no business trying to put a combination together without some knowledge of what you're doing.
Just a few of the things you need to understand....
Block deck height
Piston deck height
Piston compression height
Static compression ratio (you need to know how to figure this from scratch)
Dynamic compression ratio
Squish (how to arrive at it and what figure to use)
Camshaft (advertised duration, 0.050" tappet lift duration, cam lift, theoretical lift at the valve, intake centerline, exhaust centerline, lobe separation angle, overlap, timing events- intake opens, intake closes, exhaust opens, exhaust closes)
Head gasket bores and thicknesses, when to use what gasket.
Cylinder head intake and exhaust runner volumes. When to use what head.

Knowing this little bit of stuff will allow you to figure out what parts you need to do a certain job in a motor. It won't make you an engine builder, but you'll be a lot closer than you are now.

kejross, I have sent you a PM

Pat

This newbie with the typical rebuild needs to know what compression I should run with all the other components in the build... the .275 domes show 10.39:1, .125 domes show a 9.38:1 Where do I start having to use premium gas and race fuel? I'd like to run on premium or less, its too hard to find race gas around here. I also wanna thank everyone so far with the great cam break in tips. Also how important is degreeing the cam? my gear drive set has all the different inserts but I don't know anyone with the kit to degree it and Im not looking to spend 150 on a kit ill use maybe a couple times in my life...

ok with your open chamber heads i would say if you don't polish the combustion chambers them i would say 10:1 - 10.5:1 compression.

some people have luck alot higher 10.5:1 it all depends on combustion chamber efficiency, quench, timing, piston top shape, if the engine runs hot or cold, how much overlap your cam has, and so on.

it also helps if you buy aluminum heads.

p.s. go to a double roller timing chain insted of gear drive because the crankshaft sends harmonics to the valve train (not good), they've even been known to pop keepers out of the retainers(also not good). plus they take more horsepower, and they make a noise you like at first but you take a trip in the vehicle and you want to kill yourself when you are finished IMHO.

Randy