Olds1971

Today got off the phone with comp cam. Got two way different oppions. The first being 270H magnum. Duration 270/224 valve lift .501 lobe lift .313. Second is 268h duration 268/218 valve lift .456 lobe lift is .286. So are either of these plasible? The first seems like it would be pretty doggish with my set up but I dont know.

RetroRanger

need more info about your car

intended use
engine specs
rear end ratio

Olds1971

Its a 1972 350 rocket all stock going into a 1983 cutlass supreme. I still dont know my 83's rear end gears. My intended use is pure street fun/daily driver

chadman

If it's all stock and going through exhaust manifolds and a small exhaust I would get a split duration cam. Something with about 10-12 more degrees of exhaust duration at .050 than the intake. Of those two I would take the smaller one.

Olds1971

Well I guess that part I should clarify.. I will have headers and 2 1/2 inch exhaust

captjim

The problem is the compression ratio, it is around 8 to 1. Couple that with the 2.xx gears that are probably in the car (2.14 was popular) and you REALLY do not want to over cam the car. I would be very conservative, something like .450 lift and 205 @ .050. Do you already have the headers? IMO, you really won't gain much, they will be more trouble than they are worth.

cutlassefi

He needs low end torque. Using an exhaust that's 10-12 degrees bigger than the intake will only stretch out the powerband.

He needs to make peak torque quickly so I'd do something around a 214/220 on a 108, with about 6 degrees advance. He needs to retain cylinder pressure, the advanced intake timing will enhance that.

Olds1971

I been doing reasearch and your exactly right the 10-12 degrees bigger is a bad idea from what I seen. And Cutlassefi your exactly saying what I want. Do you agree with not using the headers?

cutlassefi

Headers are a personal preference thing, your call.

captjim

Mark, that seems like a lot of cam for a stock-headed low-comp 350 with no gear and stock converter in a fairly heavy car. Here is the mildest Voodoo, which I know you don't like,
http://www.lunatipower.com/Product.aspx?id=1720&gid=287
Better choice, IMO. I ran a 214/224 in a 9 to 1 355 with head work and headers, too big. 210/216 Engle ran great. For a full point lower compression, stock heads, I don't see the 214/220 on a 108 building cylinder pressure. You do this for a living, tell me what I am missing? Jim

Olds1971

Do headers at all make a difference besides sound? Sometimes I heard headers hurt you more than help in some cases. Ill let you to help me with this cam.. I really dont wanna spend all this time doing a motor that screws up cause it was a fail lol. Im a beginer here learning a trade

captjim

Stock 350 manifolds are TERRIBLE! Headers can be a significant upgrade, but it depends. On a serious build they are absolutely a cost effective upgrade, IMO. One thing that is different about Olds engines vs SBC and SBF is that in stock form two cylinders share the center exhaust port. This negates a lot of the scavenging benefits of headers. Also, if the primaries are too large, it can hurt performance in a mild build. I used Sanderson shorty headers on several builds and found them to be a nice compromise.

Olds1971

So headers it is, I have my carb im going to use(650 holly) it was on my 71 cutlass had good luck with it. stock heads, stock manifold for now, so this cam thing. If I get any cam you guys are talking about. Im going to have to change valve springs and lifters right? If I dont even better but i know lifters are a must

Olds1971

Is gears hard to change?

captjim

You must not have understood my post.

Olds1971

If stock manifolds are terrible. and headers might hurt performance whats ur choices

cutlassefi

A lot of stuff here.
Personally I'd do headers, but long tube headers. They offer a distinct performance advantage and typically you'll hear any cam more thru headers than you will manifolds, that's what he wants.
Jim- the 108 is to try to advance the intake closing as much as possible and delay the exhaust opening, building cylinder pressure. Plus I would have at least 6 degrees advance ground into it as well. He's also planning to change the gear to a 3.42, that'll help everywhere.
The generic 214/224 wouldn't be too far off except for excessive exhaust duration and the wide lobe sep(112).
A tighter lobe sep will build more power, sooner, same with a shorter exhaust, better midrange. If this thing runs out of breath at 5000 so be it. He'll have a tall gear and low compression along with the desire to hear it. That's a tall order however you look at it.

Olds1971

So these degrees advanced your talking about. like the 108 or the 6.. How do you get acheieve this? And is the 3.42 gear in the rear the best way to go for daily driver?

jensenracing77

the 108 is the degree between intake and exhaust lobe centers. the 6 degree advance is setting that 108 at 6 degrees before top dead center. that 6 degrees can be made into the cam and you just install the cam to top dead center. i am no pro...cutlassefi will make it more clear than i can.

i have 3.42 in my Rallye 350 and i am happy with the drivability of it.

cutlassefi

108 is the lobe sep and technically the intake centerline as well.
The + 6 means your installing it 6 degrees advanced from that and/or it has 6 degrees advance ground into it.

Example, cam has 214@.050 intake duration;

108 (straight up) Your degree wheel should read -1 or 1 degree after TDC when the lifter is .050 up.

108+6 (102 intake centerline) - degree wheel should read 5btdc with .050 lifter rise.

Lobe sep is ground into the cam, intake centerline is changeable.

Hope this helps.

captjim

The extra advance should help. I re-read several times and do not see where a 3.42 gear is stated, though that would certainly help a lot. IMO, and cam that has any "lope" to it will be too big.

cutlassefi

He pm'd me, sorry.
If you have enough cylinder pressure along with enough exhaust lobe you'll hear it a little.

Olds1971

This is all starting to make since now-ish. The intake centerline how is it changed? To make suer im following this. Top dead center is when the first cylinder is all the way up right?

edzolz

For an intake manifold, I would find an A4 off of a later 307. It is a very good intake for any small block. Dual plane, aluminum, can run HEI with it. DO NOT BUY AN A5.

Olds1971

Which years of 307 does the A4 come on?

jensenracing77

i don't know it's good and bad points but i have an A4 if that is what you go with.

Olds1971

Im going to do some research on them see what there all about

Olds1971

Ok top question came into big money problems and really need this motor in the car because the v6 is finally choking. If I go ahead and stay stock for now and drop it in the car, Is putting a cam in hard to do when its in the car?

DoubleV

Wouldn't the 108 lsa make the idle extremely lopey? Wouldn't it also kill your milage ( yes I know we don't build/drive these cars for milage but still )?

captjim

Yes. If it runs good and you need it in there, just swap it and rebuilt it or another one later. You do know that the V6 to V8 swap in not a direct bolt in, right? There are quite a few things that need to be changed.

Olds1971

What all needs to be changed??, trans mission is a olds 350 turbo, I have motor mounts from a 83 307 to fit the v8 mounts, I will have dual electric fans on it because it wont fit an actual pulley fan. I have an altinator for the 350 but with the plug from 83 so thats a plug n play now. The 83 has no computer, it just has the electric choke. What am i missing??

DoubleV

Pullys, accessory brackets, 4 barrel throttle bracket, and wiring. I'm sure there are some other odds and ends too.

Yes you can very much run a normal clutch fan. That's what every Olds V8 came with from the factory.

Olds1971

Im using all the original pulleys, no use for bracets, im a 2barrel with a two barrel going in so im already set for that.Idk about wiring yet, for the cultch fan idk if I would have room to run one

DoubleV

I think you need to do some more research before taking on this project. For one, you said you have a V6 in your car right now right? Well that's a Buick engine and so you will need a matching set of brackets and pulleys from an Olds V8.

Not sure what you mean by saying that you're a 2 barrel carb, but did you not state you were putting on a Holly 4 barrel?

Yes, of course you have room for a standard clutch fan. That's what all these cars came with. You need to ditch the V6 fan shroud though and get one from a V8.

captjim

http://www.robertpowersmotorsports.com/G-bodyV6-V8.html

Olds1971

Everything is staying stock for now Im dropping in it like it is before I cam it or anything else. The motor is a full motor pulleys and all. With the way my car is adding two more cylinders out I dont know if the big v8 fan will fit so I was going to use dual electric fans. Sorry for the confusion just a change of heart atm. Im not using anything at all from the v6.

Olds1971

So I read that link. I knew I had to change the fuel line direction, Already have the 307 mounts from 83, Im only using wiring for the alt,starter,coil,dis and blower motor. Im not using dumby lights anymore I have very nice gauges in there place. my dumby lights never worked right anyway. I dont have a/c never have had it and right now wont have it for awhile. So far the only thing on conserned about is the clutch fan?? you think one from a v8 would clear?? Idk about that one

DoubleV

For the third time now, the V8's all originally came with clutch fans so why are you so concerned with a clutch fan not fitting if that's what all of these car's originally came with? Go to a boneyard and look at any Olds 307 setup. They all have standard clutch fan setups. You're concerning yourself with something that you don't need to be concerning yourself with.

olds 307 and 403

If the V6 rad looks questionable, replace it. Replacements are only around $100 and a good idea. Next look at a 3.08 or 3.23 gear set, if your keeping the 3 spd trans. Unless you like running 2800 rpm on the highway at 60 mph with the stock tire height, don't go 3.42.

Olds1971

Ill take a look at them. And because someone told me that the length of it wouldnt fit that it would hit the radiator. And when people keep saying frame brackets from a 307. There talking about the lower frame mounts that bolt to the frame correct??