Randy82WS7

anyone happen to know the duration, lobe lift, and LSA for the carby HO 305 engines ?

wanting to know if the stock replacement CS274 cams are worse or better than the factory L69 ones

if they are worse then what would be a good cam replacement for a stock HO 305 ? *for low end playing around town only power*

Sealed Power - CS274 Camshaft .390/.410 Lift - 194/202 Duration @ .050
112* LSA

thanks

sofakingdom

iTrader: (1)

That cam is the "929" cam.

It's crap. Way worse than the L69 cam. It was the one used in all the smogger motors of the 70s.

I'm too lazy to go measure the L69 one I have on the shelf. However, if memory serves me right, it's around 203°/207°, .415"/.430".

The 204°/214° Summit cam, 1102 I believe is the #, is an approximate "replacment" for the L69 one.

For an improvement, look at the Comp XE256 or XE262.

LAFireboyd

iTrader: (3)

sofa was pretty close, 'cept his memory combined the specs for the L69 cam with the specs for the '88/'89 LB9/L98 cam, making it similar to the '90-'92 cam.

The L69's cam specs are basically the same as the '87 LB9/L98 cam... the '87 cam being a roller version of the L69 cam. '88/'89 LB9/L98 cams were the largest of the generation. And '90-'92 were a combination of the '87 and '88/'89 cams, using the '87 duration with close to the '88/'89 lift.

L69: 202/206, .403/.415, 114.5

'87 LB9/L98: 202/207, .404/.415, 114.5

'88/'89 LB9/L98: 207/213, .415/.430, 117

'90-'92 LB9/L98: 202/207, .413/.428, 114.5

It's right here:

https://www.thirdgen.org/techdb

The specs for that Sealed Power cam you listed, Fast, would be like a compromise between the '86 "peanut" cam and the L69 cam.

Randy82WS7

ok cool good info


it looks like its going to be this so far:

XE256H
milled 4416 heads
Z-28 springs
headers
1700 summit converter



thanks

F-BIRD'88

Don;t bother with the 1700 stall converter. It will not give you a higher stall speed from the one you have now.
Most off the shelf converters are rated when used behind a typical 350ci motor. When used behind a 305 motor the actual stall will be lower by a bout 300-500rpm from its listed stall.
B&M #20402 would be just right for you.
get some 3.73's

Randy82WS7

yeah rear axle swap for a deeper ratio is definitely in the plans, im definitely not keeping the crapola geared 10 bolt thats under it, i will find a basic 3.42 or 3.73 10 bolt for around 150 at a yard here, that alone will help noticeably..

im still confused on a camshaft, i just want to find one thats the very next step up from an L69 one

but im having a real hard time with that

too many numbers

what about the XE250H or the XE252H ?

it looks like the summit 1102 is too much of a step up for what im doing

im after low end torque, for playing around town lower speeds

im not really much interested in hi rpm performance


soo.,.. what would you put in it?

remember all stock 305 and around 9.0 DCR

and would stock 67-69 Z-28 springs be ok ? or?

thanks

F-BIRD'88

Stock 1967-69 302 Z28's came with stock GM springs "068"
Nothing special about them. There was and is a replacement stock diameter "143" spring that was a match to the optional Z28 "140" off road cam. They were very popular hi perf replacements of the day.
Comp 981's and Lunati 73943 springs do the same or better job and generally cost less. Genuine GM parts are expensive.

You seem very confused as to exactly what you're after.
if you want low end torque out of a 305 keep the cam small. If you put in a larger cam the torque band gets shifted up in rpm. Even the L-69 cam shifts the power up quite a bit from the small "peanut cam" that is stock in the LG4. The 305HO motor that came in Monte Carlo SS cars is the same L69 motor and came with a special 3000 stall lock up converter
in the TH2004r trans. You can take that as a hint. a "1700 "rated stall converter is not going to cut it. it will get you about 1400-1500 behind a 305.
if you want more get up and go (low end torque,acceleration) put some gear in it. 3.73's minimum. 305s are short on torque and need all the rear gear that they can get. The stock intake manifold will make the most low end torque. A performer will make more midrange torque. A RPM will make even more mid and top end.
A summit 1102 is about the same size and rpm range as the 305 L69 HO cam. A 305 with long tube headers and a cam like the summit 1102 or the XE256 and higher 9.5 ish compression ratio, ported stock heads, 3.73's and a high stall converter will go very, very well.
If max gas mileage is the most concern then stick with a small stock like cam like summit 1101 cam. stock intake manifold,2.73's and the stock converter.
Porting the heads and raising the cr will help reguardless. So will headers. it won't go as good as the HO version but will be a little better on fuel for long trips. Around town won;t make much difference.

if you really want power get a 224 to 230deg cam like the comp 280magnum, a 9" 4000stall converter and 4.10-4.56 gears cr should be 10-10.4:1 750 holley and RPM manifold. fuel mileage will be big block ish but you'll blow off a few big guns too.

LAFireboyd

iTrader: (3)

Is the block pre-roller('86-) or roller('87+)... or is it pre that you'll be retro-fitting to a roller? Because if it's roller or being retro-fitted, cams that are very close to what you want that might still be available(though GM, which = $$$) are the roller cams from the '87 LB9/L98 TPI(L69 specs) or the '90-'92 LB9/L98 TPI(a derivative of the L69). Specs are on my previous post above.

Those will be the closest to what you're looking for, and many TPI engine parts are still available. But there's still another option, something exact... have you considered having an "L69" cam custom ground?

If you go through Summit, who offers custom grinds from Comp and Lunati, the price is very reasonable, even affordable. And since no one seems to make a cam close to L69 specs, a custom grind might be just what you're looking for. It's, at least, something else to consider.

Fast355

iTrader: (2)

Here is what I found when I was still messing with the 305 HO.

The LE9 (van/truck version of the L69) cam was 202/206 @ .050, had .403"/.415" lift, and was on a 115* LSA, GM 14088843

The GM 24502476 cam is also a good cam to run in a 305 for overall good performance. It was used in the 300 HP crate 350 and IS still used in the 330 HP 350 HO crate engine.

I dyno'd my stock LE9 305 back in 2000. My stock 1983 305 was just over 10:1 (measured the stock pistons .025" in the hole, flattop with 4 valve reliefs coming in at 6cc, stock wafer style shim head gasket @ .018-.020" compessed and 3.9" bore, as well as stock 52cc heads, I am tempted to say the factory goofed with a L69 shortblock and LE9 top-end) compression and had the L69/L81 cam in it. Stock with the 52cc 601 casting heads, stock aluminum Q-Jet manifold and stock Q-Jet with DR rods and a F-hanger. Layed down 165 RWHP @ 4,700 and 252 RWTQ @ 3,200 through cast iron manifolds and the factory Y'd dual system with the pellet style 2 1/2" cat. I was not really dissapointed. It made those numbers despite only having 24* total timing @ 4,000+ rpm!!!!! I recurved the distributer to provide 32* of total timing @ 3,200 rpm (with the initial set at 12*) and the initial timing was set from 4* to 12*. At that time, I discovered that someone had dicked with the secondary air valve adjustment screw. I went 1 turn from Zero tension and things really kicked up. I also used an air valve pull-off canister from a 1970 350 HP corvette 350 that pulled off in less than 1 second, vs. the stock 3-5 seconds. I also replaced the pellet style cat with a new high flow monolith style and removed the stock muffler for an aftermarket single in, dual out turbo style muffler, leaving the stock manifolds. It then made 176 RWHP @ 4,800 rpm and 281 RWTQ @ 3,200 on the same dyno in very similar weather conditions. The converter that came in it from GM stalled at approximately 2,200 rpm behind the stock 305, but I did have 3.08 gears. The stock 700r4 shifted @ 5,500 rpm with the pedal burried. Stock tires were Firestone P225/75/R15s.

EDIT- I was looking at an EngineParts catalog that listed a cam that suspeciously has the same specs as the L69 cam and is actually listed as the stock replacement cam for 1982-1988 305s. Here are the specs listed in the catalog.

Cam Part # 229-1871
Cam Kit Part # K840

It is listed as a MPG cam

202* Intake Duration @ .050
206* Exhaust Duration @ .050

269* Intake Duration @ .006"
271* Exhaust Duration @ .006"

Cam Lift is

.269" Intake
.276" Exhaust

Gross Lift is

.404" Intake
.415" Exhaust

The LSA is 114.5*

It is installed on a 115* intake centerline and has an exhaust centerline of 114*.

Timing Specs @ .050"
IVO = 14* ATDC
IVC = 36* ABDC
EVO = 37* BBDC
EVC = 11* BTDC

I never had any complaints about lack of low-end torque. It would fry the tires with 3.08 gears and P255/70/R15s on my 5,500# conversion van. This is after the TBI conversion, but the engine was still otherwise stock with about 215,000 miles on it.

http://youtube.com/watch?v=Oi_n0goatA8

PS- thats BOTH tires

Randy82WS7

ok good info thanks

i am confused on the torque converter stall issue

how could an L69 need 3000 stall ? and why wont 1700 be any good ?

how does this work ?

i was thinkign 1700 was a bit much, but 3000 ??? wow...


how do you determine how much stall you need or how much rpm slippage you need ??

what am i not understanding/seeing ?



thanks

Damon

One of the things that helps torque production is a tighter LSA (Lobe Separation Angle). Stock cams are very wide, obviously, at 115-117* (helps emissions and fuel economy). If you get something down in the 110-112* range, even with the same duration as stock, it's going to make better midrange torque- which is exactly what you want on the street.

The other thing that helps is the fact that almost all aftermarket cams have about 4* of advance ground into them where the factory cam has, basically, none. That helps in the low-midrange torque department as well.

One of the smaller Comp XE cams that you asked about would be a good choice. I wouldn't get TOO conservative with the duration, however. There's really no need to go under 200* @ .050. Something in the 200-210* range on the intake (little more on the exhaust) will run like a raped ape. It might be a little softer than stock at 2000 but by 2500 it will catch up and then pull away considerably from there up.

I know you don't want a high RPM screamer with a soft low end, but don't go so far towards low end torque that you flatten out the horsepower and end up with a dumptruck engine. 2500-4500 is where it's at for a strong street performer.

A stock converter will work with a mild cam like this- it will hold a stable idle in gear and drive around sharply. A higher stall converter would work better, however, even with a stock cam if a strong lauch is what you want (and you have the traction to use it). You might not want to go as far as 3000, but I wouldn't bother with anything less than 2200-2300. The difference between stock and 1700 is not enough to justify shelling out for the new converter and not enough that you'd notice much difference anyway.

Randy82WS7

ok so XE250H and torkmaster 2400 converter

should the cam go in straight up, or should i advance, or retard it 4 degrees ? *for lower RPM useage*

with the 4416 heads

3.73 gear

that good ?

isnt that a bit much stal speed though since the cam is only 600 to 4600 rpm ? and also since the 305 engine isnt going to breathe very well above 5k and since i wouldnt run it above 5k anyways?

it is just going to be for fun around town only

setting timing will be the next endeavour and trying to figure out what would be a good initial and total setting

any pointers ?

how do timing tapes work?

i would assume that timing tapes are different for different balancer diameters, right ?

no ?

anyone out there running 3.73 gear with a 305 and XE250H ?
how much stall speed are you running ?
and where is your cam set at ?
and what springs are you using?
timing ?

i dont want to end up with a dog, like i did last year when i stuck a summit k1104 cam in a stock 1970s year 76 cc 350, it was horrible trying to accelerate until it hit around 3k then it would start to go finally, stock converter, 2.73 axle, it was a nightmare :/

so thats why i scared now





is it even possible to make any lower rpm torque from a 305 ?
is the 250h cam going to add any above stock, or do i need to look at another cam ?

i really just want to increase the bottom end, i dont care about high flow or higher rpm or any of that,
even 4600 rpm is alot to me, i never take an engine that high unless is a loaded down dump truck, etc, but the trucks has hi-torque engines with lower rpm torque and little hp and they didnt use higher stall converters and stuff,

the lower rpm toqrue is what i want from this 305,
if its not possible then i need to quit now

thanks again

Fast355

iTrader: (2)

GM did the dumptruck/ RV engine thing well with the L03/L05 engines. Strong torque from 2,000-3,500 and FLAT above that. Too bad GM did not put the L69 cam in all the TBI engines. We would not think of the L05 as a 200 HP weakling if they had.

Randy82WS7

ok point well taken lol


so what cam is good pulling at 2500 to 4500 rpm but fine for a stock 305 at the same time ?


the 2400 converter would be great then

right?

i only have one chance to do this right and the 170 bucks for the cam and lifter kit is a ton of cash money in the world of poor-dom


lol


because if i settle on a cam and it ends up being a dog and not working out then im going to be really pissed off and will never touch a camshaft ever again, or maybe never an engine again,


im starting to feel that i shouldnt try and do anything with this engine and instead just run it with the headers i already have and a 3.73 rear from the yard and the 2400 converter, and live with that much til some day i can get a bigger engine or maybe put the 400 in it

because the stock rating shows the LG4 to be 240 torque @ 2400rpm

if i go with the 2400 converter then wouldnt i be putting that much torque out at take off then ?

id be really super happy with that alone.,


thanks

F-BIRD'88

When you see a "1700 stall" converter in say the Summit catalog. it refers to the expected stall speed when used behind a typical 350ci motor. A 305 ci motor produces less torque than a 350 does. therefor that same converter will not give a 1700 stall behind a 305. it will see about 300 to 500 rpm less stall or 1200 to 1400 stall. Thats is all you will get.
Smaller motor= less torque output= less actual converter stall. If you put the same "1700 stall converter" behind a 454ci motor you would see about 500rpm more stall than the rated stall or 2200 stall. why? because the 454 ci motor has more torque. more torque output=higher actual stall speed.
So If you buy a "3000 stall" converter from the catalog and install it behind a 305 you won;t get 3000 stall. you will get about 300 to 500 rpm less stall or 2500 to 2800 stall.
Just right for a 305 with a Summit 1102 or XE256 cam, headers. ported stock heads and 3.73's.
If you buy a "2400stall" you will only see about 2000+/- behind a 305. won't be enough to get the effect you are looking for.

That "3000stall" that will only deliver about 2500 to 2800 stall tops behind your 305 will still drive around town just fine. But when you floor it WOT the tach will go to 2500-2800 rpm (right into the strong range of the motors torque band) and the car will accelerate hard.
Do not buy the "2400stall" it will not be enough.
YOu will have a dog.
On a small ci motor the converter stall speed and rear gear ratio must be carefully matched to the camshaft torque range.

Any questions?

RodsRideSS

A few years ago,...I pulled the cam out of my 87 Monte SS HO 305 with a CCC q-jet:
Roller Cam... with 180*-210*@0.050" and LSA 114, lift was around .400"-.430" ...this engine was stock. the cam was suppost to be the same as the 87 corvette cam, but I think this one is better for low end and exhaust scavenging. Anyway,... it's not the specs that I expected and I couldn't research the #'s...i think i'll take another look...i have on the shelf still !

ohh...by the way, replaced with 217*-223*@0.050" and 112LSA with .500 lift
Ported and bowl blended World S/R torquer 305 58cc heads, Headers, MSD, stock aluminum intake{couldn't cross ref the #'s on it either}, tricked out 200r4, and 3.73 gears with stock 1900 stall lockup and Spintech exhaust.

This thing runs awesome!!

Damon

I think your Monte SS would be the "freak" if it came with a factory roller cam. The L-69 HO motors all came with a flat tappet cam in them, even in 87.

But I'll never say never. I had an 87 305 TBI Camaro with a flat tappet cam in it, when it was supposed to have a roller (and it also was the original engine).

Nobody ever believes me on that one so I'm not believing you about the factory roller cam in your 87 Monte SS!!

Fast355

iTrader: (2)

87+ was a roller camshaft in the Monte Carlo SS (L98 hydraulic roller). The 1988 Monte that I last worked with had a stock TBI 305 HO in it. Factory TBI setup on it. It was NOT a swap.

RodsRideSS

LOL..."freaky" yes..the block is cast stamped with the #627 which means Roller Cam casting. Check your block for this number. Pull the valve cover and look down the oil drain hole for the factory roller lifter retainer.
My SS is USA built, July 1987...seems they were evolving into getting the fuel injection system for this car with the emissions controls, small distributor with external coil, ECM program changes, and apparently the chip for this car is the best chip out there for timing control for that period and setup!
Maybe this car had some changes made to help with Research and Developement, I don't know...but I couldn't find the the cam number code and the intake stamp code is not in the chevy manuals that I've researched,...I'll get the numbers again and throw them out there...maybe someone could shed some light on it for me!

atc3434

iTrader: (4)

What cam did you end up with? I have a build similar to what you were discussing, and it works really well. The K1102 with a 3.73 rear and a 2500rpm stall works great with my LG4 305. All the mods are in the sig. Plenty of low end torque, I'll blow the KDW's off pretty easily, and makes good power on top. I shift at 5500rpm from 1-2, and 5200rpm for the rest of the gears. Makes power all the way up there too, really comes on over 3500rpm.

RodsRideSS

Yup..I know what you mean! That HO305 really woke up with the changes I made...and still about 23MPG...I'm very satisfied with the results!
Herbert Cams Roller 217*-223*@0.050" 111LCA .500"lift....Idle @ 800 with 15" of vac.
1900 stall{Stock}, 200r4 with trans-go shift kit and corvette servo, 3.73 rearend. 1-2 shift is 6000...2-3 5200...This tranny will full throttle upshift and lockup in 4th gear from the factory...which is unusual{I was told}!
World S/R torquer305 ported and bowl blended,port matched with 1.94's and 58cc. Roller Rockers!
Headers with Spintech mufflers no cats or emmissions and stock computer with "SuperChip"...not sure who makes that!

atc3434

iTrader: (4)

I bet that setup would love more converter. Still with the cc-qjet and ignition?

RodsRideSS

Yes...I would like about 2200-2500 stall but I was in a pinch to get it running and out of my Garage when I changed jobs and relocated. Someday I''ll get at it again!
Still using the CCC q-jet with MSD ignition & coil and Billit aluminum Distributor, Accel module. The q-jet is new and I had to recalibrate it for the new setup...the setting are nowhere close to stock. I've recorded everything I've done to get to this point...i'll dig it out and post it FYI !
I'm into electronics...I needed to boost the vacuum voltage with this street cam so built a tiny voltage regulator to do that...it solved the lockup issue I had and it got the timing advanced back to where it should be.
Also...I'm using 160* temp with the chip, but I have to look into some closed loop issues....may switch back to 180*.