V8 Tuners! Lets talk roller rockers...

[ToolsnTrack]

OK gents (and ladies i guess, lets not discriminate)

I have a cam and lifters sorted. Got 1 week left in Africa then its home to fit them all. Reckon i can squeeze another ton out my budget so i think a set of Roller Rockers may be on the list. Now my Chevy, from what i gather, is 1.5 ratio stock. Owing to it being an 82 smogger i don't want to risk bending valves so i think getting a stock ratio set of roller rockers may be best. First question is, does this logic compute?

Second, i see a lot of "3/8" and "7/16" stud diameter getting thrown about. Is this an engine specific requirement or is it better to get the 7/16 as its some sort of upgrade?

Lastly, should i be considering anything else before splashing out? The 2 i am looking at are these:

cgi.ebay.co.uk/Crane-Cams-11744-16-Rocker-Arm-Set-Chevrolet-/110612985655?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19c10c3737

cgi.ebay.co.uk/Crane-Cams-11745-16-Rocker-Arm-Set-Chevrolet-/110612985689?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19c10c3759

FYI, its Hi Intensity lifters i have, incase this affects what decision i should make...

Cheers in advance for the collective shared wisdom! I promise mods, there will be pictures as soon as i get back to support these tech threads...

[akku]

increasing the lift ratio increases lift at the valve without increasing the cam lobe.

However it does risk altering the geometry of the valve train. You may need custom length pushrods to prevent this. This will depend on the cam profile and a bunch of stuff.

I would say your risk of conflict comes from the narrow bore of the 305 as much as anything, remember the valves are set at an angle... If you have bigger valves in a head upgrade you have less space for the latteral shift as they open.

Now next question is "does your cam require adjustable valve train?" because most hot cams do. Your stock rockers do not allow for the kind of adjustment necessary so aftermarket adjustable rockers may be necessary anyway,

You may also see *some* power going for a 1.5 roller rocker. The lift and the geometry don't chnage but you'll get the adjustability you need as well as the reduction in internal friction.

Stud diameter is the diameter of the stud in the head. You may be able to drill and tap 7/16" studs into a head which came with 3/8" studs (most stock heads). the bigger studs are used to allow more rigid mounting of the rockers when you use very high poundage springs. Not an issue with your application. Only wild cams need those kind of springs. They are also of use in very high RPM applications.

[ToolsnTrack]

Alistair, i don't reckon i need and adjustable valve train, as it said nothing about it on the crane website.

In that case i may go for the 1.5s with a 3/8 stud. There will be no way my heads have any sort of performance fettling done, and I'm not looking for wild power, just a decent street upgrade. I alos doubt that once i've done this cam out upgrade that i will be changing heads etc in the future...

Once again, many thanks for the input Alistair!