V-8 305 Cam. What size???

1981 18ft bow rider Checkmate V-8 305 190 Hp, 4 barrel carb. After finding the lifter would not lift pushrod. Took motor apart found out lobe total ground off cam. This was #6 Cylinder Ex Valve. This is Bull crap i think we should see if it is coverd on warrenty by GM. I wish it still was 1981. HA HA. Everything else looked good. Copmpresion test 130psi on 6 cylinders # 1,2,3,4,7,8 150psi on #5 cyinder and 115 on #6 cylinder. Ok not so good but good we found the problem. Need new cam and lifters. My Question is should we beef up alittle or just stick with stock. does any one have any input on duration and lift we should go with. P.S. i know it just a puky 305 but it is what we have and dont have money to buy a new motor.

Re: V-8 305 Cam. What size???

You have a 305 and you will not make a noticeable change by putting in a lumpy cam. Replace it with a stock cam and be happy. HP is made with cam, compression, and carburetion so making one change doesn't accomplish much.

Re: V-8 305 Cam. What size???

The flat hydraulic cam used by Mercruiser in their 350's is readily known. (I can post specs this evening). I have heard it said it is the same cam in the 305's, but I have not tried to confirm that. Check the cam part number between the two engines for that year to be certain. I do not see any benefit going larger than that in a 305.

Re: V-8 305 Cam. What size???

make sure you add a zink break in additive, the oils now days have eliminated it, rollers cams dont need it, ive heard alot of fresh motors fry the lobes and lifters with out it

Re: V-8 305 Cam. What size???

I think you can get a cam&lifter set from Summit for like $99 or so

Re: V-8 305 Cam. What size???

Thanks all. orderd new cam, lifters, timming chain and gears. From Summit, should have them by wed. will post results after final assembly and start up. Happy Boating

Re: V-8 305 Cam. What size???

81 Checkmate said:

Thanks all. orderd new cam, lifters, timming chain and gears. From Summit, should have them by wed. will post results after final assembly and start up. Happy Boating

Click to expand...

Well, I forgot to post the specs, but wondering what you picked?

Re: V-8 305 Cam. What size???

John Thats Ok. I went with a Summit K-1102 Cam and Lifter set and also got a Summit dubble roller timing gear and chain set, All for $ 147.95 shipped to the house. I had looked on E-Bay but i didnt trust what i was looking at plus with Summit it has a warrenty. I did all the prep work on the gasket surfaces last night and ready to put it back together. Hope when i get home it's sitten on the porch. They said 1 to 2 day's out of there Ohio warehouse. We live in Cincinnati so it looked good to get parts in that time frame Will post when i have everything back together.

Re: V-8 305 Cam. What size???

Better late than...

Stock 350/305? hyd/flat cam:

Lift: 0.400I / 0.410E w/1.5r
Dur: 200 / 212 @ 0.050" lift


Summit K=1102 Cam:

Lift: 0.420 / 0.442
Dur: 204 / 214

Looks just a little more than stock, should be good.

Re: V-8 305 Cam. What size???

Again Thanks John. i wasent sure what the spec's were for stock. but when i was looking i had seen this one it is for a truck/RV cam. it ranges from i think 1500 to 3500 RPM and that was what i was looking for.I put the cam/Lifters/ timing chain and adjusted the rocker lash last night Hope i can get everything back in tonight and firer it up. will let you know. Happy Boating Everyone

Re: V-8 305 Cam. What size???

Update!!!! Well stayed up till 2 am on thursday and 2 am on friday. Got the boat fired up tuned in the hyd lifters while boat was running. Adjusted Points.Timming and fine tuned carb. Kept it running for about 45 min to break in the cam. Shut her down check for leaks looked good. Got up early Sat morning hooked hose up and it firerd right up let run for a few and hooked up trailer and off to the lake. Arived at lake around 2pm drop her in the water fired up and 1/4 mile no wake zone. eased up on the throttle and buzzed around the lake for 10 min shut her down open lid and alls good. I am grining ear to ear now going great. Buzz around a little more bring her up to 3/4 throttle great running good head back to dock and open lid look under motor and oil all over the bildge area. So i think F!!!! now what, got to looking around and on the port side the valve cover gasket was sticking out on the bottom by the ex manifold. Which is the ***** side. So got out the RTV and cork Gasket let it set up up and stuck it back on. All is good now runs great ( had to replace the Plugs, old ones looked good no oil foul ) had it up to 52 mph. Over all i am very happy with the Pukey little 305 Motor. For Just a little over $200 bucks for all the parts and two oil changes. Not bad. Thanks All for the Help.

Re: V-8 305 Cam. What size???

Cant beat that, gotta love a SBC. Can get parts for 'em at the local 7-eleven!

Was there any MPH difference between the old cam and new one?

Re: V-8 305 Cam. What size???

Yes i did gain some MPH. Before i could get it to 47 MPH on a com late day run very smooth water. Over the weekend it was a bit choppy and i had it to 51 MPH. I would move the throttle up some and watch the MPH gauge (Tach Broke) and then trim up untill i didnt gain any MPH and so on till i had WOT, it did get a little squrily at times and i thought this is great this thing runs good. I think if we played around with props we could get a few more. That will be Next season. My son wanted to sell the boat after got it running. but after i took it out i just fell in love with it Grinning ear to ear. I told him i would buy it from him. 1981 was a long time ago and it probley has seen alot of water. It still needs work but as someone earler said fix one problem at a time and enjoy. The next project will be replacing the lower shift cable. I would like to fully restore someday. Time will only tell. Happy Boating