What size are the studs in a bone stock 86 305 tpi motor? I'm guessing 3/8?

What's the stock rocker arm ratio?


Thanks!

 

You are correct, and they are press in units, your rocker ration will be 1.5, so the factory says, in reality due to mass production tolerances they may be several different ratios on the same engine however little, we have saw them from 1.42 to 1.54 over the years. A new set is a good investment even if they are not rollers, but that would be a better decission, then you are assured of the correct ratio. Why do you ask grasshopper....LOL. If your looking at a larger cam, you for sure want to get a new set because it impossible to get anything degreed in without proper valve trane geometry.

 

Thanks Zeeya for the info. Yes - I'm contemplating a mild top end rebuild (305's and TPI are new to me and stock they seem very slooooow) and trying to figure out the correct combo for a strong occasional daily driver. I was looking at some 1.6 rollers (possibly 1.5 depending on cam), new cam, springs, pushrods, ignition overhaul and upgrade, adjustable fuel pressure regulator, SLP intake & runners, ported throttle body, & SLP cold air box. Exhaust is stock except for a Flowmaster so it will need to be opened up too. SLP headers are a possibility and I might opt for some headwork which would definitely include screw in studs. I'm trying to work up the cam specs. I was thinking 214/224 & 442/465 at 50 but that might be a bit aggressive so I should probably stay in the 204-214 range with slightly less lift. Any recommendations on a good cam?

 

Exhaust should be the first thing to upgrade. No use helping it breathe in better when it has to blow through a coffee stir straw. Start with headers.

 

Yep - SLP's will be going on. All work will be done at once.

 

Good choice, exhaust first. The cam should depend on alot of things, for instance your gear ratio, if its a stick or auto etc, If its and everyday driver then keep to the smaller side of your decissions. If your going to spend much on modding your heads you may want to think about some aftermarket ones. Remember money spent on induction is money well spent. Since its a 305 cid I would work on the torque aspect of the engine so dont get crazy with runner size, and over lift/duration on cam, I would strongly suggest call comp for there ideas on cam selection, but make sure you have all your info ready for them, that way you will get closer to the optimal selection. You should at that time take advantage of upgrading your entire valve trane like the springs/ pushrods/ timing chaine etc. Good luck