small block chevy timing.

You are gonna smoke a piston at 36 total. I'll bet it lunges at starting?
Mine is pretty tight and the best I can get with 90 octane gas is about 12* base with about 28 at 4000 running a Thunderbolt V system. It runs really well there/ Any higher and it will start to ping. I would like to squeeze that last degree out and I may yet, just haven't done it yet.

Chevy was a factory option... OMC offered the 307 then 305 and 350. PCM offered the 350 later as well. Of course, they all spun the proper way.

And a side note, I believe I will be buying another prop. I went out the other day and twisted her to 5500 RPM and it would have gone much further.

This was going off the factory tach so that could be off by some. I dono??

Hey some of us love our Chevy boat motors

Not that it applies but I turn the OJ 13 square 4850 at 48 mph with 280 estimated hp. 1979 SN

Correction 12.5x12

baitkiller wrote: A stroker with Vortech heads? So sweet. What did you do for a cam? I have been quietly shopping heads while the wife is asleep. Just the heads and intake will take me to 310. Being a lefty I can find a cam for short money to go further. However I run in salt water so intake plenums are extremely limited. I am interested and a bit jealous of your project. But if it aint lunging at 16* base I got nothing for you. Out of my league.

Bait killer, im still running a stock cam. Im just testing this for now. If it gives me problems im going to snatch it out and run the 350 during the peak of the summer. Still might pull it anyway untill i get the cam i want. I dont have the prop selection tim has and the cam could possibly change that too.As for as the motor its not stroked. Its a fourty over 400 with 5.7 rods and steel splayed mains with a steel crank, stock out of the box vortec heads and performer rpm intake. It does have the stock gearset pcm used and mixed 1.5 int and 1.6 exh roller tipped rockers.

Tim what is your timing on the big block all in? I know the BBs dont like as much timing as small blocks just trying to get a safe number. As I said before if its pinging at 36* I cant tell. Is it noticable above the exhaust note? (No mufflers)

I think you are backerds.. Big blocks run more timing..
Now i gotta Google it, should have done that first.

Ill show you mine....

This is the 350. 400 looks no different. I havent took any of it yet.lol

Vic, your Tique sounds very average to me. I've seen stock 302's and 305's run anywhere from 45 to 51mph in the 16'5" hull. 47-48 is the norm. My skier is about the slowest example I can think of- it has touched 47 but is a 45.x boat on any given day. It tracks 1:1 speed vs rpm with the 1210.

I would think that even a bone stock 260hp 350 should push one of these hulls over 50 easily.

You never updated us on the bent shaft... You seemed convinced the Acme shook the boat. One of us should dig that thread up and update it for anyone reading it in the future.

I want to say we run around 35 total timing on our 454. It doesn't ping now, it was obvious when it did, you could hear and feel it loud and clear. Our engines are miles apart of course, big block vs small, were a tad over 10:1, etc. I know less about SBC's than just about anything.

Slight to moderate chop will result in a faster top speed, as it helps introduce air under the hull. Bouncing speeds you up as well. With 400ci, you gotta be all of 350-400hp, so I'd be surprised if you weren't close to 60.

Tim the bent shaft went with my buddy to his work. He is a cnc supervisor. He put it on a machinist table and said that he couldnt get a three thosandths shim under it anywhere. I installed in the boat and found later that was bent just aft of the log. And yes I need to update.sorry...lol. what fooled me was that the federal didnt amplify the issue like the acme did.. I guess ill keep it at 36* and keep my ears open.



Bait killer, pretty cool serp set up. Been contemplating it but the sherwood pump is going to screw me unfortunately. Also shes loud and proud with the copper tone already buddy. First mod was copper pipes...:-D

Vic cool project...if the heads haven’t already been pre prepped for bigger lift cam you will need to work on the vortec valve seal height/spring pads or longer valve stems and beehive springs over around 470 lift... machining is easy to do with the right cutters and hand drill, rocker posts are best changed from push in to tapped screw in type.

Keep us posted on your build.

Roger.

Remember, Higher the compression, both static and dynamic, will require less final timing. Stroke/rode ratio are also serious factors.

It has to do with the speed the flame front travels (faster with higher compression) and when peak cyllinder pressure occurs. Spark plug placement and combustion chamber shape are also factors.

So, to sum up, lots of numbers supplied here, but when one makes a stroker, changes heads, pistons and cam, thre is no 'chevy's run this' simple answer.