ok Have it narrowed down for cam uh I think

by Limey SE Sun Dec 17, 2017 12:22 am

Stock bottom end 46k mile 305ci adding Holley 600, Hi rise manifold, Monte SS heads ( if no improvement going to world products sportsman Iron heads) Hedman long tubes

Cam Choices below I like the last one the best BUT will wait to hear from the experts on matter I HATE HATE HATE choosing cam

https://www.summitracing.com/parts/lun-10120701

https://www.summitracing.com/parts/lun-10120702/overview/

https://www.summitracing.com/parts/sum-k00172/overview/make/chevrolet

http://www.jegs.com/i/JEGS-Performance-Products/555/200105/10002/-1?ymm=4294829809+4294829791+4294829288

ok Have it narrowed down for cam uh I think 21439410

ok Have it narrowed down for cam uh I think 21439410

ok Have it narrowed down for cam uh I think 21441410

ok Have it narrowed down for cam uh I think 21441210

by 1975 S3 Sun Dec 17, 2017 12:42 am

Is that the GM marine intake? I grew up in the town that used to make Johnson/Evinrude stern drive motors and a few of them used to filter out onto some street builds
.

by Limey SE Sun Dec 17, 2017 12:49 am

no its an aftermarket (low end) Manifold my car is a 1977 so got the GM corperate blue ICK ICK

by 1975 S3 Sun Dec 17, 2017 1:00 am

Limey SE wrote:no its an aftermarket (low end) Manifold my car is a 1977 so got the GM corperate blue ICK ICK

sorry, thought it looked like one of the stern drive intakes, they weren't great but if you had had a line on one they were better than the standard GM 4bbl intake and they went on a lot of 305 boats, Doral etc.

PS. had a buddy in high school whos dad worked at OMC, built the engine for his 76 lemans out of OMC part nos.

by pila Sun Dec 17, 2017 7:55 am

If your compression ratio is under 9:1, a log duration cam will make your engine a slug for sure. The last on that list would be a bad choice for a low comp ratio engine. I've had best luck with the 305 engines, with the Comp Cams HE252 cam. Even used one in a friend's boat 305 Mercruiser, that had trouble pulling skiers up on the water, and it made enough more power/torque to do the job....

Just my own experience of course...

by Joe73 Sun Dec 17, 2017 8:01 am

#3 and #4 would not be my choices due to operating range and required compression ratio. They would be sloppy without a looser stall and a bump up of compression.

My question is, why mess with the cam on a 45k motor? Need to race it? Your cam is already broken in so no issues there. If you need a quick bump of power, hit it with a 50 shot of nitrous. A 50 shot would be in the ball park of doing your heads and cam but with only installing a spacer plate. Safe, cheaper and way easier to install and the looks you'll get at a car show will have everyone wondering whats in the motor. Just my thought.

by bracketchev1221 Sun Dec 17, 2017 8:33 am

Cam 1 or 2.

by brownbomber77 Sun Dec 17, 2017 9:44 am

I would definitely do a converter and gear first. Anything above 220 degrees of duration is gonna be slow off the line with a gear below 3.42.

by Joe73 Sun Dec 17, 2017 9:46 am

brownbomber77 wrote:I would definitely do a converter and gear first. Anything above 220 degrees of duration is gonna be slow off the line with a gear below 3.42.

I agree !!! Best bang for the buck. Gears will give a very noticeable seat of the pants feel.

by Limey SE Sun Dec 17, 2017 12:33 pm

brownbomber77 wrote:I would definitely do a converter and gear first. Anything above 220 degrees of duration is gonna be slow off the line with a gear below 3.42.

Remember Brownbomber I do have that rear you brought here it has 3.42 and 3.73 gears I am building for it so trying to get the Cam choice to match whats going in there

by Podor Sun Dec 17, 2017 12:41 pm

I've kicked around some upgrades on my low milage 305 until I swap it out. The problem with the 305 is the bore vs valve size. The valve on the stock heads are tiny, it think a 1.72 intake. On a 350, you can get some low priced Vortec heads for cheap that give an instant compression upgrade and great flow. On a 305, to just maintain the compression ratio and a larger valve, you only have a few options. World makes a nice iron head with a 58cc chamber for about $600 each assembled. You might be able to find a Vortec 305 head, but you would still have to machine it. Any cam you get will be limited by the heads. I wouldn't recommend going though the trouble without heads. At that point, you are looking at $2000. For a little more $, you could get a Vortec long block from GM for $2055. It's already set up for a roller cam, so all you would need to do is upgrade the cam for 350 HP easy. For me, I'm just going to enjoy the 305 as it is an wait to assemble what I need for the future LS swap.

This is a great article if you want to use the 305
http://www.superchevy.com/how-to/engines-drivetrain/1412-how-to-mod-a-305-with-bolt-ons-add-168-rwhp/

by Limey SE Sun Dec 17, 2017 2:41 pm

Podor wrote:. World makes a nice iron head with a 58cc chamber ... I already have 85 SS Monte Heads are already 58cc Valve size: 1.84"/1.5" Intake cost of 1/16th of the world heads for about $600 each assembled. You might be able to find a Vortec 305 head, but you would still have to machine it. Any cam you get will be limited by the heads.
This is a great article if you want to use the 305
http://www.superchevy.com/how-to/engines-drivetrain/1412-how-to-mod-a-305-with-bolt-ons-add-168-rwhp/

I already have 85 SS Monte Heads and they are already 58cc Valve size: 1.84"/1.5" Intake and lets just say the Family Dinner cost more than the heads I have....... I also have everything That the Article says to get....... Long tube headers, 600 carb, almost Identical intake, 2.5" exhaust

by bigredlaguna Sun Dec 17, 2017 2:51 pm

The heads for the magazine engine IMO are where the biggest improvement was made. They have the largest valves possible, and a modern combustion chamber. You could get the same cam as the magazine engine and show us the difference between the best factory 305 head and the aftermarket one in the article.

by brownbomber77 Sun Dec 17, 2017 3:14 pm

3.42. You’re not doing a transmission anytime soon are ya?? Ha. Unless you want my neighbors 700R4 from his Caprice. 85,000 miles on it... Hell, take this engine and trans, stick the heads and Cam into this one so you don’t have to edit with it inside the car. Do the converter all in one fell swoop. After nit picking at this Olds for 13 years, I regret not collecting parts for a while and then just doing it all at once.

by marx3 Mon Dec 18, 2017 7:59 am

with 416 or 601 heads, you should be u paround 9.5:1 unless you installed a thin head gasket. My own ´79 350 has 416 heads with a .020" head gasket and stock pistons. I am right around 10:1.
I mistakenly put in a Summit K1103 288/298 advertised and 214/224@050. Because of the long advertised duration the engine is a complete dog up untill about 3000 rpm. I should have kept the advertised duration in the 270's. That 274/274 adv. 218/218 cam on your list looks good, apart from the 106 LSA. The best choice on your list is the lunati 10120702, although your engine propably dont need a split duration cam.

Edit: just saw that you have a 305... in that case the Lunati 701 is the only way to go on that list. The last one would be insane to install :-) a 282/292 adv. 224/234@050 would be pretty healthy for a 454. In a 305 it would be huuuuge

by brownbomber77 Mon Dec 18, 2017 5:49 pm

One more thing. Summit has a $50 mail in rebate on Detroit Lockers. Get yourself a Tru Trac and forget about wearable parts. Then buy the rear discs I have...haha

by Iggy Fri Dec 22, 2017 12:08 pm

I know I am new here, but I have been wrenching on cars for over 40 years. When looking at the RPM range listed from the manufacture, that is based on a 350 small block (big blocks listings are based on a 454). For every increase in 50 cubic inches (or decrease) you need to add 8* in .050" lift duration (or decrease for a smaller engine) to have the same effect as the rating. For a 305 you would want a cam with 7* less duration to act the way it is listed for a 350. Another thing to consider is that Chevy exhaust ports are weak and in most cases with stock heads you want 10* more exhaust duration to help make up for the weak exhaust port - TBI truck heads it is almost 20* needed.

Advertised duration is something that can be picked anywhere so beware of that figure. GM uses the actual point that the lifter starts to rise, Crane Cams uses .004" lobe lift while Comp Cams uses .006" lobe lift. A better way to compare cams is the .050" duration and the lift - if you have two cams with the same .050 duration and one has more lift, the cam with more lift will have better cylinder fill (volumetric efficiency) and thus make more HP and Torque.

Considering your heads, I would either go with your first choice (Lunati 701) or a Summit 1102 - anything bigger and you start to loose low end torque in a 305. Also, 112* LSA is better on the street than 106* LSA.

by BBMALIBU Fri Dec 22, 2017 5:40 pm

What happened to all those hot rod 305's that members were building?
Maybe one can recommend a cam that they used.

by brownbomber77 Fri Dec 22, 2017 6:09 pm

Hot rod 305
Lol

by Dead Man Fri Dec 22, 2017 7:25 pm

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