Intake or Headers which should come first?

[Anonymous]

I'd like to get alittle more get up and go into my '78 250 in a Granada..any suggestions??? Totaly stock right now.
Thanks

 

[rbohm]

8) on these little sixes, and most any stock engine for that matter, headers and exhaust will gain you more per dollar spent. in the case of the six though, you have to change heads as well as the intake in integral.

 

[AzCoupe]

Personally, I think the best, first upgrade, is the ignition. Either a DurasparkII & MSD, or the DUI setup that I sell.

Search either topic on here and you'll find a lot of info on them. There's also a couple of stickies at the top of this section on the DSII.

 

[Lazy JW]

I thought a 78 Grenada already has the Duraspark 2 distributor
Joe

 

[JackFish]

I went for the double-roller timing chain first. Especially if the original is still in the engine. Then I would do camshaft and head.

 

[AzCoupe]

I thought a 78 Grenada already has the Duraspark 2 distributor

Obviously, I wasn't paying attention.

 

[CZLN6]

Howdy Back G-Man and All:

Unfortunately, your Granada 250 is suffering from several limitations.
*Low compression at 8:1 advertized. Probably lower in reality.
*A restricted exhaust system.
*An overregulated and complex carb. A '78 will likely have the last itterations of the rare Carter YF for a 250 engine, or possibly a Holley 1946.
*Retarded cam timing.
*Too high a final gear ratio and too heavy.
*The 250s have way too much deck height to have efficient combustion.

Given these limitations simply changing carbs or adding headers would be expensive and disappointing.

A good place to start is to advance your initial timing by 5 degrees over stock setting. Make sure your climatic air intake system is working as designed. Make sure you catylitic converter is not plugged. A 2.25 or 2.5" exnaust system would sure help. Do all you can to lighten the rig. Switch to a 180 degree thermostat.

The single biggest thing you could do to increase the way this car feel is to change the stock rear gear, which is probably a 2.78:1 to a 3:1 or 3.2:1. Since this Granada should have a standard Ford Fox 8.8 rear end finding a 3.00:1 should not be too difficult, but a 3.20:1 could be a challenge.

What trans do you have? Wha is your stock rear-end ratio?

Adios, David

 

[rbohm]

8) david, the granada from the 70's came with the 8" or 9" rear end. the 8.8 rear end was not put in cars untill the early 80's, and then in the fullsize cars. the fox body didnt get the 8.8 untill 86 iirc.

 

[CZLN6]

Howdy All:

As always, the devil is in the details. Thanks for the correction rbohm.

Changing the center section in an 8" or 9" is much simplier, and again a 3.00:1 should be fairly easy to find.

Adios, David

 

[LaGrasta]

I went for the double-roller timing chain first. Especially if the original is still in the engine. Then I would do camshaft and head.

double-roller? How does this increase performance? I thought this only added durability.

 

[JackFish]

A few reasons, first would roller-bearings.
If your old chain iss due for replacement, like mine was, timing was difficult and had starting problems.
Extra strength to handle all that power you'll be building into your motor.
It has nine keyways that alow you to advance or retard the valve timing up to 6*. I have mine in at 4* and you can feel the difference.
If you are installing a new cam this would be a typical swap during the job anyway, and Mike sells the best chain you can get. If you are installing a hi-po cam and a nice shiny head, why wouldn't you want one in there?
I think of it as starting from the bottom up, cause the way I sometimes drive, I don't want some old piece of crap in there waiting to fail and destroy my motor.

 

[LaGrasta]

thanks for the explanation. When my motor is dead or I get the bug to start a new build, I'll definately be writing FSP a bunch of checks.