200ci rebuild

[rt67stang]

Ive finally decided to get the original motor rebuilt. I know for sure that it is going to have a 250ci head on it. the things im not sure on is how much to bore it out, and Wat cam to use. i only want a mild cam something that wont make it sound like crap. i was thinking about boring it 30 over, does that sound good? Any advice here would be greatly appreciated
Thanks, Ronny

 

[69.5Mav]

Bore it out only as much as is needed the clean up the bores.

As for cams there are others here with more experience whom I expect will shortly chime in.

 

[Gene Fiore]

The following two cams from http://www.classicinlines.com would be good choices...264 -110 or 264/274 - 110

 

[rbohm]

8) as indicated, when boring a cylinder out, you only want ot go far enough to make it round again.

as for the cam selection, the first thing you want to do is decide what rpm range your engine will spend 80% of its time in, and then select a cam that works in that rpm range. for instance on a street engine meant o be a daily driver, you want the cam to work in the 1000-4500 rpm range. pick a cam in that rpm range, and match the rest of the parts to complement the cam, and you will have a strong engine in that rpm range.

 

[chad]

will spend 80% of its time in,
rbohm
Very helpful (new info to this I6 junkie). Hope I aint jackin this thread -

So W/ a stock 1v, low rev, hi tq, 87 octane - that info still holds true?
...1500 - 2500/3000 rpm...
(don't wanna spin the tires, just haul)

Thank you,

 

[sp_alloy_head]

rt67stang,

Seriously consider balancing the internal rotating assembly, it's extra $ but not it's not that expensive. Hold off on spending your cash on "BLING" and focus on things that will make it run reliably.

 

[rbohm]

will spend 80% of its time in,
rbohm
Very helpful (new info to this I6 junkie). Hope I aint jackin this thread -

So W/ a stock 1v, low rev, hi tq, 87 octane - that info still holds true?
...1500 - 2500/3000 rpm...
(don't wanna spin the tires, just haul)

Thank you,

8) yep. remember that the cam is the heart of the engine. it determines in what rpm range the engine will operate most efficiently. improving airflow into and out of the engine just makes the engine breath better and allows the cam to do its job more efficiently. but one thing to truly understand is that everything has to be matched in a systems approach for best operation. for instance, using a cam that works best in the 1000-4500 rpm range wont help when the headers you use are designed for high rpm. or say you pop for one of classicinlines aluminum heads, grab a cam that operates best in the 1500-5000 rpm range, and use a nice set of street headers, but then choose to put on a 1050 holley dominator carb. with this combination, the engine will fall flat on its face until the rpms get up to about 3500-3000 rpm so the engine can start using the massive airflow the carb is capable of, but by that time the engine more than halfway through its power band, and that little 78 diesel rabbit has long since left you in the dust.

 

[CZLN6]

Howdy Ronny and all:

It'd be good to know what trans you'll be using? What rear-end gear ratio? What vehicle? ('67 Mustang is my guess) What is your intended use for this engine? What compression ratio? What other mods or improvements like- intake, ignition, exhaust? The answers to these questions will help us to be more specific with suggestions.

Keep it coming

adios, David

 

[chad]

roger, I AM a systems thinker! (building science; family, organization & other human systems, culinary science, etc). Thanks...

 

[MPGmustang]

like others have stated, depends what you want.

IMO if your going for the 250 head go for a direct mount 2bbl, the HP increase will be felt in the seat of your pants and you'll be grinning ear to ear.

I really enjoy my 264/274 110* CSC, it has a great bottom end torque (150-167 depending what carb and air temp) and usign the 1bbl mounting hole, I have made 127hp with a 2bbl adaptor, now if it was direct mounted I'm sure I would be in the +140hp range. now over stock I was pulling 68hp
the only down side if there is one, is I make the HP late, roughly 100+hp around 3500rpm (ATM with a 1bbl)

the bore, if your not going blown, keep it round and healthy, IIRC the more you bore out the more heat the cyl walls soak and less heat is expelled out the exhaust.

balanceing the engine will produce a smoother running experience and IMO a more even wear and tear.

for street gas a 9.3:1 CR is good, depending on elevation you might be safe running 87 oct.

let us know some more specs, you can tell the forum 'lights' up when someone is about to rebuild thier i6