BigJustinZ28

hey guys , I have an 84 z28 with the 305 HO L69 on it. Ive had it for a while. Recently I bought a 97 z28 (lt4 swap w/ hotcam etc) . Now I feel its time for the 84 to go under the knife. Im currently in the process of trading someone for a set of vortec heads , after thats done in a month or so Im going to get either a performer or rpm vortec style intake. My question is this. My friend thats gonna be helping me do this had an ole iroc he swapped an ole 350 in and used a 488 488 lift cam on it with vortecs. Right now I have 2 cams I am trying to decide one.
Duration @ .050" i/e max lift i/e
Cam #1 224 / 224 .465 / .465
cam #2 224 / 234 .465 / .488

What do you guys think of this ??? Any other suggestions on cams ??? Also will my compression drop alot from the swap ?? Im going to try and get the 650 quad to work with thit setup , but if not should I go 650 holley or 750 ??? I want this to be one extreme 305 .

Stingraye

Of the two you have listed the 2'nd would be better, but i'd look at comp cam's XE cam's, they have a wide variety, and it's only liked $100 for a cam kit. Also, only go with the 650 on there if it's only gonna be for a 305, I had a 700 mechanical holley on my 305 (after the 350 blew), and it was just way too much fuel for it, so I would got with just a 650 and u'd be fine.

F-BIRD'88

Both those cams are too big for a 305 even with vortecs.

Unless you;re going to use a 3000+stall converter and 4.10's pic a smaller one.

Find a cam with a intake duration of 204 to 216 @.050

a crane H266-2H comes to mind

210-216 @.050 .440"/.454" 114LSA

or a comp cams 265DEH dual energy cam
211-221 @.050 .442-.465" 110 LSA

A good street 305 cam,, even better with vortec heads.

Vortec heads have 64cc chambers stock 305 heads have 58cc chambers.
Your compression ratio will be lower if you just bolt on vortec heads.
You could have then milled to 55cc or so to get the cr up.

The bigger the cam you install the more critical it is to have the cr right. 9.5-10:1 is good.

BigJustinZ28

well I have the ho motor which has 9.5:1 cr with the stock heads on it , is there any calculation I can use to find out what the cr would be with the vortecs and how much I need to have it milled ??? Also what kind of horsepower you think Im looking at if I went with the 265 DEH as that looks a lil better. I was actually thinking of a stall converter in the future for it would this cam still benefit with a stall converter ???.

F-BIRD'88

You can play with the cr numbers here.

compression ratio calc

every .006 you remove from the deck of the head will reduce the chamber volume 1cc. ( approx)

Yes that cam would benefit with a higher stall and some gear.

If you have the 305HO cam now try that one.

BigJustinZ28

I dont understand what you mean by that . where can I find my piston deck clearance ??? and Im guessing since thier flattops dome = 0cc ???

F-BIRD'88

the 305HO cam is a good high performance grind.
If that is what you have try it first.

you have to measure piston to deck clearance at TDC
typically .025" or .045" on chevys..
Stock chevy head gaskets are .015" thick. sSome replacements are thicker .039" some are the same.
Flat top pistons have valve reliefs about 5cc's volume
you may or may not have flat tops.

BigJustinZ28

I was thinking about just putting 1.6 rockers on there with the HO cam , it would be a lil less extreme than the aftermarket cams but would have pretty good lift numbers , I think in the .430s .440's with 1.6r , dont quote me on that tho. But I figured since I already had the heads off and the cam has almost 190k miles on it I'd go ahead and do a cam. This 84 amazes me sometimes , 190k miles and runs better than most with a 3rd of those miles. Its all in how you take car of it. I bought it off a drag racer (pro street , it was his wifes car). It was immaculate at 140kmiles when I bought it and I have taken great care of it since then.

Ray87Z

Definitely do the cam while you're in there with everything apart, makes zero sense to stick with the stocker IMO when you've got it all apart anyway, it's not what I'd call a particularly good "performance cam". Sure it is better than the peanut cam but.... If nothing else spend $100 and get something like the generic 204/214 .420/440ish cam Summit and several other companies offer. I ran that cam in my 86 IROCs 305 (TPI, stock heads though) for awhile, decent cam. I like the specs on the 265DEH listed above myself, seems ideal especially for a carbed motor with a decent set of heads...

BigJustinZ28

yeah Im really thinkin about that 265DEH cam , isnt that the one some guy used to pull 400hp outta a 305 LG4 car with vortech heads and a modified victor intake ??? I believe it is. But the torque peak was real high like 4800rpm , I think that may have been the victor intake and the fact that the heads were never milled so they had a huge combustion chamber , correct me if Im wrong.

Ray87Z

Not familar with a 400hp buildup, but Car Craft got 325hp out of a 305 LG4 with a CompCams XE262 (218/224 w/ .462/.469 lift, running that in my Vortec 350 BTW) and some Victor intake and Vortec heads. They stated that was a little hot and would need a 5spd or highstall converter with the 305. I think the 265DEH or something similar right in the 210/220 range for duruation seems just slightly smaller enough to work a little better for a street car, but still pretty mean...

Here's the scans for that article if you want to read it BTW. Had them up on my webpage for awhile but lost my space and thought they were gone, luckily I backed them up, just found them the other day and got them back up...

http://www.dcpnet.org/stuff/305Buildup/page1.jpg
http://www.dcpnet.org/stuff/305Buildup/page2.jpg
http://www.dcpnet.org/stuff/305Buildup/page3.jpg
http://www.dcpnet.org/stuff/305Buildup/page4.jpg
http://www.dcpnet.org/stuff/305Buildup/page5.jpg

For theirs it says .045 was milled off, and .015 head gaskets were used to get up at 10.0:1 compression with LG4 pistons, don't know of the L69 had different pistons or not...

BigJustinZ28

my friend (the one who was gonna help me with the head swap) has talked me into just going ahead and doing a 350 swap , which makes sense cuz the vortecs would be good on that and they are almost a dime a dozen. He did a similar setup on an iroc he had. He has also offered his help with this as Ive never done a motor swap before. Im sure this will end up being one hell of a learning experience. , ill keep you guys posted. He was running a .488 .488 max lift cam on his car (dont know the duration) he says that stuff about .480 max lift on stock vortec heads is bull. Anyone else run that kind of lift on stock vortecs ??

F-BIRD'88

Your friend is probabily crushing the tops of the valve seals on his motor.

All the sets of vortec heads I have checked all had less then .490" clearance between the top of the valve seal and the bottom of the stock vortec retainer.
One only had .450" clearance.
Take your friend's help with thanks but take his advice with a grain of salt.
Check the clearance yourself.

BigJustinZ28

well Im gonna have the heads tanked and get them rebuilt with a 3 angle valve job , what can I have done to them to safely run more lift ???
thanks , Justin

five7kid

iTrader: (14)

Have the top of the guides cut for positive stem seals, and the seat pockets cut for larger diameter springs. Typically done with a single tool. Then you can use better seals and better springs.

Retainer to seal clearance should be checked at assembly. .060" more travel than max valve lift is considered safe.

BigJustinZ28

cool , Ill let the guy know what kinda rpm I'm gonna be probably running with the cam and its specs and have him tell me what I should have done to achieve this safely .
"Have the top of the guides cut for positive stem seals, and the seat pockets cut for larger diameter springs. Typically done with a single tool. Then you can use better seals and better springs. "

what do you think a reputable shop would charge to do this and what springs and seals would you recommend ? I dont know much about heads beyond combustion chamber size , valve size , and max lift , lol . Im still learning , this will be my first engine assembly I have done.