[vette427-sbc]

I am looking to buy a new set of heads and a cam for my 350. it was originaly a 350/350hp so i assume it has domed pistons. what is the max lift that you can run on this car without clearancing the pistons?

btw- i am possibly getting AFR 195 heads and a lunati hyd. roller lifter cam. the specs are 298/296 duration and .478/.482
there are 2 cams like this but one is signifigantly more what makes that difference http://store.summitracing.com/compa...94840140+4294887624+4294889107+4294837295+115

 

[vette427-sbc]

anyone??

 

[JPhil]

I cannot help you as to whether or not you have domed pistons & what clearances you have/need, but I do feel obligated to say you should do some studying and learn more about how cams, heads, carb & exhaust and all the components of an engine have to work together to provide good performance. Just bolting on these heads with that cam without understanding the interrelationship of the entire package, from carb throats, intake runners, valve lift & duration, compression ratios,etc., thru exhaust ports & pipes will only result in lots of money spent and you complaining that it doesn't run like you expected. You can ask a million questions on the computer, but a few days with a couple books will give you the ability to ask better questions and thus get better answers.
I suggest you start with "The Complete Guide to Street Power" by Jay Storer and then "John Lingenfelter on Modifying Small-Block Chevy Engines", both available at Amazon.com. There are also many others of similar content available.
Learn before you spend: you'll get more for your money.

John

PS: a hydraulic roller cam is not-repeat-not just a bolt in on a flat tappet SBC. AFRs are excellent heads, but 195s may possibly be too much unless you build the motor to make the most of them. (Others opinions may vary!)

 

[vette427-sbc]

i have done a decent amount of research on what i am looking to put in my motor. the AFR heads i have heard and read that they are very nice, and i also compared them to other heads that were in the same category. they out-flow most other heads. i figured that a 195 cc runner would be big enough for a pretty hot 350 while being small enough to keep the velocity up also.
the cam i picked is still a very streetable cam, making power in a useable RPM range and an LCA that is a little wider for a "smaller inch" sbc.
aside from having to run link bars on the lifters for a hydro roller cam, what else would i have to do?

 

[JPhil]

427--

:laughing: Sorry, dude--I saw you were 17 and looked through a few of your posts. Didn't see much engine mechanics talk, so I 'assumed' you didn't know much about motors....oops.
But now I must say, I can't really help you: I was always into motorcycles, this is my first car project in 25 years. This is the first car engine I ever rebuilt, so I am not conversant in too many modifications. But I can say I spent a year studying & getting ready (I returned 2 cams before going with the one I have, based on my research) before I jumped in, and I am very pleased with my results. My hot-rod buddies gave me a lot of grief about how mild I was building it, but when I showed them my dyno sheet, they were all very surprised at the numbers and had to admit I had put together a strong package after all....
So I'll leave you with a 'bump' and a 'good luck'!:thumbsup:

John

ps: your Summit link doesn't bring up the cams, so I can't look at the specs to see what the difference is.

 

[vette427-sbc]

no worries, i tend to surprise many people with my engine knowledge, so im used to it. on your sb, what are the specs on your cam?
here is the link to the one that im looking at http://store.summitracing.com/partdetail.asp?part=LUN-54761LUN&autoview=sku
hope this one works

 

[JPhil]

Mine is Comp Cams XE262H flat tappet dual pattern:
Adv. duration, 262/270. Dur @ .050, 218/224. Lift, .464/.470 LSA 114*

Your Lunati looks like a real nice choice. Not too radical, good lower end torque because of the wide LSA. Good street cam.

Investigate the AFR 180 heads: The smaller cc runners increase the velocity of the intake charge to pack the cylinders better, and less mass in the runner means faster acceleration of the charge into the cylinder when the valve opens. This enhances lower end torque. Bigger cc runners work better for high RPMs when you're moving a lot more air.
I am very very pleased with my AFR 180 heads, well worth the money if you can afford them. Im surprised nobody has responded to your query about retrofitting the rollers.

Are you familiar with this place? I get a lot of good info there http://www.hotrodders.com/forum/

John

 

[Fred Mann]

I'm no expert on hydraulic rollers, but I have one in my car. You need a thrust button, for sure, since a roller has no self-centering slope to the cam lobes like a regular hydraulic or solid lifter cam (the slope on the lobe and the convex shape on the lifter underside give the spinning motion to the lifter). Some belt drives might take care of this also. You need a front timing cover that won't flex under the force imposed by the cam if a thrust button is used. You also need to make sure that the gear on the distributor and the drive gear on the cam are compatible materials. Besides the valve lift, you need to know the closed and open spring pressures that the cam requires, these will be more than a similarly sized flat-tappet hydraulic cam, but less than a solid roller. With the cam spring requirements, you can select the valves springs you need to match the cam with respect to spring pressures and coil bind. Or pass the info on the the head supplier.

 

[JPhil]

427-- Here's something you might want to check out:

http://cgi.ebay.com/ebaymotors/ws/e...0104491834&category0=&fvi=1&item=200104491834

John

 

[vette427-sbc]

that looks like a very good idea, but it looks like you would have to drill and modify the block, which i do not want to do because i dont want to pull the motor apart to clean from metal shavings, otherwise i would be building a killer sb.
thats pretty interesting and i will keep that mod in mind
thanks