cubemaniac

The engine I have is out of a 1993 Buick Roadmaster wagon.

I want to build it up slightly and I've decided I want to put a bigger cam in it. It has the stock iron heads, pistons. Engine will be carbed with, I'm thinking about 670 or less cfm.

I want it to lope, you know all the stuff a 19 year old would want in his 86 IROC.

Anything else you need to know let me know and I'll do my best to tell you.

Damon

Don't got too big with the cam or you'll hate it- misery to drive an over-cammed motor.

You are limited on how much lift your stock LT1 (cast iron) heads can take. The limit is probably about what a Vortec cast iron head or other typical factory heads will take- about .470 when the retainers will smack into the valve guide/seals. Now that's a roller-cam motor you've got there so you won't find many roller cams that are "lumpy" with under .470" lift. Something like the LT4 "Hotcam" would be about what you want, but it will give .525" lift with the 1.6 rockers it was designed to use. Even if you keep using your factory stamped 1.5 ratio rockers the peak lift will be ~.490". Too much for your stock heads.

Not to mention the stock valve springs won't stand a chance of controling anything close to a "performance" cam.

Are you prepared to pull the heads and spend more money for valve guide machining and to have better springs installed to work with this "lumpy" cam you're looking to install? If not, you might want to keep the stock cam in it for now.

zz4monte

Also the hot cam needs more gear, and stall to get the benifts of it.2500+ and 3.42 gear-3.73. Hotcam is a big upgrade from stock. Something like this two might work better.
GM845 214 224 488 509 lift 112 lobe seperation
Comp Cam XE270HR 218 224 495 502 lift 110 lobe seperation

These are the hotcam specs
218 228 525 525 lift 112 lobe seperation (also the duration on the hot cam is really 2-4 degrees more than advertised because the 218 228 duration is before the 1.6 rollers.Hot cam also pulls easily passed 6000rpm.

You also want lope you say? Well a tighter lobe seperation and more overlap with help with that. Go for something like the comp 270hr or 276hr but you will have to have a little more stall, if you don't put headers on its a waste of time.Also you will need something along the lines of a performer rpm intake.
You want to do the whole package or the cam swap will not benifit you that much.Headers,exhaust and intake can easily make a bigger difference then just a lopey cam.

Sailfishchaserf

If you want lope, comp has the new thumpr series camshafts, which are designed to lope at idle, but they dont give you good #'s. Basically just a cam made for all show.

SpitotRs305

i bet those stupid thumpers are undrivable for a daily driver

cubemaniac

I would be willing to have the head work done, if it wasn't insanely expensive. How much are we talking about here? I am on a budget but maybe I could squeeze it in if it's not to much. I also just remembered that we swapped out the IROC cam out of the 305 into this LT1.



I have this intake picked out:

http://store.summitracing.com/partde...8&autoview=sku

I was planning on putting a Holley street dominator 670 cfm on top. Or should I go less?

I do want to put headers on. I'm thinking of these two and having a buddy make it a true duals exhaust. I have no emissions tests to pass by the way.

http://store.summitracing.com/partde...5&autoview=sku

http://store.summitracing.com/partde...5&autoview=sku

So what I'm hearing is if I have no head work done that I shouldn't put in a bigger cam?

Gumby

well allot of them old cars that loped was from a lack of knowledge but I mean no cracks by that. Kinda like back yard mechanic work. They just stuck the biggest cam they could find but still able to use hydro lifters.Wasn't always the best choice but it was the style/fad. Like jacking the rear end 60ft in the air. yellow traction bars with little red lights in the end. Oh and blue dot tail lightsand everyone had a monster CB whip attenna.

SpitotRs305

well each shop has its own prices and i wouldnt just run down the street to the guy with a drill press and have him do the work but look around i would probably expect in the 100-150 range

cubemaniac

I might have to do some looking around but I live 20 mins from Lingenfelter's shop so if there are no other places around I could always go there. But the 150 price range, is that just including the work or all the parts also?

SpitotRs305

just the work... lingenfelters.... holly crap expect to pay in the thousands from them

cubemaniac

@ the lingenfelter. Yea I just thought it was cool that I lived so close to them. Ok a new question: would it be worth it performance wise to get a cam that will work with my stock heads? If you think it would are there any specific summit links you can provide me with. I usually try to figure this stuff out on my own but these cams are hard to understand and pick what will suit me best.

SpitotRs305

well performance wise no there are very few that would be worth doing a swap and for small gains when you could have the heads machined for the extra clearance now and be able to put what ever cam you want in the future... no it wouldnt be wise

Damon

Let me step back a minute and ask a few questions....

350 cubes?

What intake design was the motor originally? TBI?

I somehow originally got it in my head that you were starting with an LT1 out of a later 90s Roadmasher, but in 93 I think they were just TBI motors, either 305 or possibly 350ci. Whatcha starting with here?

zz4monte

I don't think the 93 version was the Lt1 based motor, hence 260hp. I think it is alot less, like 180-210hp but I am not sure. The Impala ss guys make good power on those motors with a few mods but you have the swirl port junk TBI heads. At least I think? Maybe someone else knows but I think 94 the Buick got the Lt1 260hp?

cubemaniac

Yeah it's the crappy TBI 180hp version.

Damon

OK, I got my bearings now. That motor has the farily lousy swirl port heads on it. DON'T put money into the heads. Save your pennies and get a better set of heads, like a set of Vortecs modified for higher valve lift.

A big cam in a stock TBI engine is going to be no fun at all. And you certainly don't want to spend money opening the stock heads up for more valve lift just to stick a big cam in it that isn't going to work very well with those heads anyway.

Now I will grant you that the stock cam in any TBI motor of that vintage is a pathetic pig. Just about anything would be better, but again, not too big. A stock LT1 cam would be a nice upgrade- many guys here in the TBI section have done it with good results but that's about as big as you want to go with the stock swirl port heads. Now if you get better heads on it then yes, you could stick in a considerably more aggressive cam.

Also, I've used that 300-38 intake before and it's a slug. I know the price is right, but it's just not much for performance. A standard Edelbrock Performer will beat it easy- you should be able to find one used for cheap. With better heads and cam the Performer RPM would be an even better choice.

If you want a cheap intake that will work reasonably well on 87-up bolt pattern heads, then check this one out from Summit (it's same price as that Holley intake you're looking at):

http://store.summitracing.com/partde...6&autoview=sku

It's the previous generation of the Weiand Action+Plus intake which was about on par with the old version of the Edelbrock Performer. Either would work better than the 300-38.

87-up bolt pattern heads are kinda oddballs. The aftermarket doesn't have nearly as much to offer for them as they do for either standard intake bolt pattern (86-down) or for the newer Vortec style heads (which the aftermarket has gone ga-ga over).

cubemaniac

Does summit sell a cam the same size as a stock LT1?

Damon

I'm sure they do, but the reason I suggested it is you can buy a perfectly good used LT1 cam on the internet for almost nothing.

cubemaniac

I have the heads from the TPI 305 from an '86 IROC too. Any possibility that I can put in a bigger cam in with those?

InfernalVortex

iTrader: (4)

How much lift can 083's handle?

Sonix

iTrader: (1)

The TPI 305 heads are 081 heads actually.
Most stock heads can take the same amount of lift before you need to modify things. It's not exactly rocket surgery, you can get a machine shop to do it for $50 or so, or buy the tool for $50, or try to use an angle grinder and a steady hand.
Those heads are actually worth using - if you're willing to dig out the die grinder and port 'em up real nice!