Waking up a 350

[mtnrat]

I am going to make a few changes on a 50 hr, 350 that I have. It is a low HP version with the following specs.
crankshaft type - reground/polished cast crank
piston type - Sealed Power cast/dish pistons -16cc
camshaft specs -
intake duration is 202 @ 50
exhaust duration is 212 @ 50
intake lobelift is 262
exhaust lobelift is 272
110 degree lobe seperation

valve specs - 1.94 (intake) + 1.50 (exhaust)

compression ratio - 8:1

I am going to change a few parts with some extras I have laying around.
For the heads I have a set of assembled bowtie vortec small port heads. For the cam I have a compcam XM256H. I will put a vortec bowtie dual plane intake and top it off with a Qjet.
So essentially i am changing the cam, heads and intake. It pains me to use the dish pistons, but I don't want to put much money into it.
Should wake it up a little with some good manners.
It is going to go into a 17' Double Eagle deep V.

 

[Mkos1980]

Re: Waking up a 350

Nothing wrong with those dished pistons. With -16 pistons 64 CC Vortec heads, and I am assuming a 30 over block, decked to clean block, and a .039 gasket your looking at right under 9:3:1

 

[Mkos1980]

Re: Waking up a 350

I'd run a Edelbrock RPM Vortec intake. Dont go for the low rise. I noticed no loss in bottom end with my Air-Gap RPM.

 

[mtnrat]

Re: Waking up a 350

I am running an air gap on my 383 and it works great there, but I am using parts that I already have lying around. So the bowtie dual plane it is.

 

[John_S]

Re: Waking up a 350

The bowtie vortecs, you are talking the ones that come with larger valves (202 I) than the standard vortec heads, correct? Must be nice to have them sitting around Regular vortecs would match the other components beter, but if its what you have. Shouldn'tbe that bad of a mis-match.

 

[mtnrat]

Re: Waking up a 350

Yea they are the ones with the larger valves. I bought them when I was building my 383, but discovered with the 64cc combustion chambers I would have to find a -28cc D dish to get to 9:1 where I wanted. I ended up getting a pair of 72cc engine quest heads, that worked with a -16cc D dish piston. Basically I was buying parts before I had the engine properly thought out, and blew a bunch of cash on stuff I shouldn't use. Lesson learned. When getting components do enough research to make sure they match BEFORE you buy.

 

[Mkos1980]

Re: Waking up a 350

Why are you shooting for 9:1? The stock 350 motor per my MerCruiser book is 9:3:1

 

[mtnrat]

Re: Waking up a 350

Basically because if I am out on the chuck, many marinas only carry regular gasoline. These marinas are on Islands and only carry diesel or regular. I wanted to make sure I wouldn't have detonation problems.

 

[John_S]

Re: Waking up a 350

Why are you shooting for 9:1? The stock 350 motor per my MerCruiser book is 9:3:1

Yes, but if you run everything thru a calculator it isn't that high. Using the stock dished pistons, thick stock head gasket, 64cc heads, standard SB deck and components, you will see that the number is just under 9. What is interesting, is when they went to vortec heads, they upped the spec in the manual, but the vortecs have the same size chamber as the prior (217?) heads.