Technical Ford 347 CU. IN. STROKER ENGINE--NO VACCUMN

NEW ENGINE CAME WITH TRUCK PROJECT---Did no get cam card with it and the problem is NO VACUUM-- I got 5 '' at carb and intake-- rev it up I got 9 '' --NO good for brakes or other

Here is the info I got on the cam-

CAM -Hydraulic custom 497-507 LIFT

233- 238 DURATION AT 050 288 ADV 2500 TO 5800 RPM

HEADS ALUMINUM HI FLO CNC 1 PIECE SS VALVES


WANT TO REPLACE CAM WITH A MILD ONE so I have VAC- AND DO NOT WANT TO CHANGE VALVE SPRINGS--ALL HELP WILL BE APPRECIATED--- THANKS

 

1st off, you have inches not lbs. of vacuum. I have used a stock mustang gt cam with very good vacuum. If you stay with no more than 212 degrees at .050", I believe you will be very satisfied. With the mustang cam and 1.7 rockers, my 347 had great torque. If that's what you're looking for, you'll be smiling.

 

What's the cam LSA? Overlap? That's not a huge cam for 347 cu. in. Also, you should have the most vacuum at idle. As rpm increases, the vacuum should drop. You could install a vacuum canister, if you're otherwise satisfied with the performance.

My brother-in-law has a 5.0/w an E303 cam. He has to be careful pulling into and out of his driveway because he doesn't have sufficient vacuum for the brakes. The E303 has a 110 LSA, .499 lift, and 220 duration @ .050, but his engine has the stock stroke.

Do you have an automatic transmission?

 

That’s so low I’d suggest there more to it than cam profile. What’s your timing set at?

 

Answer above-- that is my PROBLEM never got a CAM CARD--

NEW C-4 trans--2800 stall converter
Canister did NOTHING I installed

Timing 12 degrees--I contacted Detroit Power that build it they were NO help

The brake pedal is HARD when you step on it the second time------all parts in this build are NEW--

 

Would like a VIDEO of someone that has a engine like this to see if it sounds like mine-- this one really ROCK sand ROLLS at idle--DO NOT WANT THAT-- ALMOST SOUNDS LIKE A big THUMB-ER CAM

 

Be sure you're looking at manifold vacuum. If you have the brake booster hooked to the carb's ported vacuum fitting it won't work. That port is closed at idle and is intended to advance ignition at cruise and low load.

 

Have you tried giving it more initial timing to see if that helps smooth some of the lumpiness out?

 

I ran an X-303 Cam in a built 8.2" 306ci SBF and didn't have any issue making sufficient vacuum. That was also with 1.72 rockers which equates to a .583" lift and had a 107 LSA.

Check for vacuum leaks.

This video is my OT car, but just referencing how lopey this X-303 cam is...Close your eyes if the imagery offends you.

 

I agree with some of the others.
My SBF has a cam 230-236 @050 with 108* LSA.(LSA is a big part of the lumpy idle BTW) Its pretty snotty at idle BUT.........its 306 cu. inch !! 347 with the same cam would be wayyy less snotty.
Check all the regular stuff.
VACUUM LEAKS at the top of the list. (SBF can be kinda tricky around the intake/carb base)
To get a snotty cam under control requires light advance springs inside the distrib. and limit the total advance to 36*.
^^^This is a haf-to !
You could put a lil girl cam in it but that's a lot of money for a problem that may not be cam related at all.
You got the right size converter....just tune the***** outta the ignition and carb. THEN i

 

Trust me the snottier the better

 

Not true. You get the most vacuum on closed throttle deceleration.

 

Butterflies not closed at idle?

If you still have vacuum at wot & max rpm, isn't your carburetor too small?

Yes, it's true, with*****erflies closed at high rpm, such as when going down a steep grade in a lower gear, the engine will produce the most vacuum. I was thinking in terms of normal driving conditions. There are few steep grades in the San Joaquin Valley.

 

What’s the idle rpm you get the 5” at? In or out of gear? Aside from how it sounds, how is it at that idle speed? Shaking, smooth?

 

Have you got the firing order matched to the cam?
For example, the 289/302 firings order on a 5.0/351 cam.

 

As others have said…not that big of a cam for a 347..

 

12 deg of initial is low , even if you have verified at top dead center of the piston and check the pointer on the balancer,
What size carb ? Looks maybe Holley ,
We can not see in pic ..
Verify your timing at top center is correct with pointer , afterwards start
With 15 -20 , start tuning with Vac gauge
Light ,,, avance timing until gauge pulls most Vac # , then back off afew degs , Note , starting point for your tunning ,,,,,,
Fast & easy way put a load on engine
About 2,500 rpms ,
(running Temp)
crank the timing up until ping , back off a few deg's .. Use for starting point for Tunning ...
""""Load on engine """ some one Holding brake in Gear !!

 

Same thing I did to my '91 fox car... 352-W B-58 with Trick Flow twisted wedge heads, X-303 cam with the 1.72 rollers, Victor Jr. Intake and a Barry Grant Gold Claw carb.... Runs and idles fantastic.....

 

Might you have a vacuum leak at the C4 modulator valve?

 

I do not have any hoses hooked up just on the intake vac outlet and only get 5 : REV it up to 2000 RPM gete 12-13 " but nothing at ideal---going to pull engine and sell it

 

I'd disconnect the power brake vacuum hose and plug it at the manifold along with any other vacuum ports to make sure they aren't leaking then measure again. Maybe your booster is bad.

When you say you're getting 12-13" of vacuum at 2000rpm, that's a steady reading while holding at that rpm?
What RPM does it idle at?


-rick

 

If it runs strong , try a vacuum pump for your brakes

 

Option

 

Since the cam seems to be one of the major mysteries in this engine, I think I'd want to break out a degree wheel and a dial indicator and try to figure out exactly what you're working with. Maybe go nuts and plot it out on some graph paper and then look at the results and figure out exactly the lift, duration, overlap and the opening and closing events.

With the cam still in the engine it might be a big help just figuring out exactly when the intake closes. The cam may not have been phased properly when it was installed. Even if you do swap it out for another cam it would be easier to sell it if you can tell somebody exactly what it is.

Or you can just pull the engine and sell it.

 

Belly*****on Chevy will get you 3 more inches and all the vacuum you could want. Just saying.

 

Plug off all the vacuum ports and see what you have. If your running a auto trans that may get funny shifting.

 

That’s a defeated attitude. You’ve been told
what to try, have you done anything?
No one is trying to cause you extra work, but dang, pull the engine to sell?
How would you describe it?

 

I have a slightly larger cam in a .040" over 351W and at idle (950) I have about 12" vacuum. When I had an auto in it it would drop to 800 RPM and 9" of vacuum in gear. Rumpity-rump at idle and engine as steady as a rock. Adding that when decelerating from speed and shifting down to a lower gear I get upwards of 19-22" of vacuum stored (gauged).

It sounds like you have a vacuum leak and the carb is opened up a bit to keep it running. Are the nozzles in your carb dry at idle (no dripping)?

 

I wouldn't SELL IT to someone with it in the shape its in.
I would just give-it-away to a Ford guy (like maybe ME!?!)
Like a friend once said to me......"If ya can't get it runnin the first time...best to just quit and whine about it !"
6sally6