i have a rebuilt LO5. does this engine have the swirl port heads or was that just the LO3. is it worth port and polishing these heads, and upgrading the spings and valves to handle my cam with 1.6 rollers.

 

throw them away, it would be a monumental task to grind down the ridges and the ramp thing that the sworl port heads have in the runners, not to mention that there probably isnt alot of material to aid with porting.

 

what heads should i look for to do some porting and add springs to handle lift above .500

 

i found some rebuilt 416's with springs that can handle .510. but the cc is 58. what would my compression be. would it be too much.

 

Your compression won't change because your stock heads have 58cc combustion chambers.

Steve

Edit: I jumped before I looked. You would probably see 1/2 to1 point rise in your c/r.

 

he has L05 heads, im pretty sure those are 64cc not 58cc.

Edit: opps, i jumped in alittle to early also, should probably read the entire post first

 

well i found some l98 heads, that im gonna rebuild. can anyone give me part numbers for good valves, seals, springs, and stuff from maybe summit that will be able to handle over .500 lift. im gonna install some 1.6 rockers and that will give me a lift of .490-.495 i believe. or i might just put in a bigger cam.

 

Your lift with an LT1 cam and 1.6's will be more like a little over .476 and .489, you might want to look at some ZZ4 springs, I've seen sets of ZZ4 springs with retainers on ebay go for pretty cheap and I'm pretty sure they support up to like .525 lift.

 

get the 58 cc heads. I think the l05 only has around 8.3 CR, and thats with 64 cc heads, if im not mistaken.

 

im pretty sure the compression on the L05 is the same as that of the L03. On a Caprice with the same exhaust, swirl port heads, cam, intake, and TBI it made 20 more HP and about 40 more ft-lbs of torque. So they had to have the same compression to make that much more power over the 305.

 

i just read a few old posts and read that the Caprice LO5 has a CR of 9.3:1 with 64cc heads

 

i think it depends on which one you have. The gmgoodwrench one only has 8.3:1 with the 64 cc heads because of the dished pistons.

 

that lower priced GM 350 is not an L05. It is a non roller, low compression, 2 piece rear main, non centerbolt, pre 87 engine.

 

so does any one have any ideas on the l98 heads

 

According to all the sources I've ever looked at, the 90-93 VIN 7 L05 is 9.8:1. My FSM agrees, as well. It also says that the L03 was 9.3:1...just throwing that out.

 

i have read that the 9C1 cop car L05 is 9.8:1 and the regular caprice L05 is 9.3:1. But i dont know what gives the cop car engine the added compression, i thought the only difference between the two was that the cop car got 65# injectors and the L98 cam.

 

my lo5 has 9.6:1 compression with 64cc heads. its a caprice cop car motor or something of that nature. At least thats what pace parts said.

 

If the 9C1 got 9.8:1, the civilian L05 did, also. I seriously doubt there is anything that different about the 9C1 L05.

Also, I have recently found out that the 9C1 L05 does NOT use the L98 cam. If you look up the part numbers for a replacement 9C1 L05 cam, the L98 cam comes up, but that doesn't mean it was originally used in the 9C1. The L98 cam is much more aggressive.