need help deciding!?

[DemonGT]

First off: I was wondering what the pro's and con's are on a 327/331 vs. 342/347??

A 342 is a 347 just NOT bored .30 over correct? what are the advantages over a 342 vs. a 347? Also..i already have a TFS street intake on my car as of now..and its only been on for about a year..so I'm planing on reusing it with a stroker and im concerned that it won't support a 342/347 therefore I was thinking of the 327/331 route, but the extra cubes would be nice.

Any opinions and info would be great..having a tuff time deciding!

P.S. would the x 303 cam be an alright cam for a 342/347?

[Rick 91GT]

The .030 overbore will give you very little so there is very little differences between the non-bored and bored stroker combo's.

I personally would go 331ci if you have to bore it out, if not go 327ci, but that Street Intake is going to hurt your power..sell it and get atleast the Track Heat if you want to stay TFS. Depending on your combo the X-cam may work good for you, I would also look into the Xtreme Energy Comp grinds or a custom cam.

[DemonGT]

Rick..i ask about the size thing cause im going to get a shortblock and CCM has some good prices and iv heard good things bout them..but they dont list a 331/347...just a 327/342...

i can see my intake hurting a 347 but i thought the street intake flowed enough for a 327/331? and the track heats lower is the same as the street heat lower so i could just get a new upper if i choose...also..whats your reason for saying 331 over the 347? isnt bigger better?

and i ask bout the cam cause they give you a x cam with the shortblock and i think the lift on it is like .542 or something like that and my buddys 347 has a custom ed curtis grind that has .550 and runs very well

[Rick 91GT]

A 331 will last longer, it has better rod to stroke ratio and even though some 347 kits have a re-located oil ring they still have issues. Yes no replacement for displacement but you need to look at the nitty gritty details..rod to stroke is one of them. A 331ci motor will last longer in a daily driver like your is.

I was going to build a 418ci but the rod to stroke ratio isn't that great so I may go 408ci

Yes you could just swap uppers since they all use the same lower I believe.

The X-cam is decent, not to sure if it will pass emissions. A larger cam isn't always better, what runs good in a buddies car may run like **** in yours. What heads will be on this motor, inj, tb, MAF. You want a cam that will make the peak power where you need it, about 300 under your shift point. A custom cam ground for your motor will not only make the most power but it could also pass emissions, and have nice driveabilty down low.

My AFM cam is fairly large, but it drives and acts so nice on the street you would never know..some off the shelf cams can not do that.

[WADS56]

I'm not trying to start a pissing contest with Rick, but the myth about the 347 is old and tired. It is older then then TFS heads having bad valve guids. Proper machine work and installation on a 347 will last just as long as a 331. O.K, now that I beat the dead horse I will move on.
I would choose a cam for a stroker (custum) not one af the alphabet cams, or one of the off the shelf cams.
almost forgot, I would do the .030 overbore. It may not help that much in cubic inches, but it will help unshroud the intake valve for better cilinder filling which I think is a good idea if you are going to have a bigger intake valve then stock.
Wade

[Rick 91GT]

Ni pissing battle here..I know that a lot of the newer 347ci are supossed to be better, but you still here issues from time to time.

Never thought about unshrouding the valves, good point You could also do that with porting the heads, valve design and chambers...

[DemonGT]

it will most likely have AFR 185 heads,accufab 70mm TB,76mm maf, injectors im unsure of as of now....but all could change over time...

also..would i need low compression pistons with a 342 if i was only looken at 5-6lbs of boost from like a A trim?

[Rick 91GT]

Originally posted by DemonGT
it will most likely have AFR 185 heads,accufab 70mm TB,76mm maf, injectors im unsure of as of now....but all could change over time...

also..would i need low compression pistons with a 342 if i was only looken at 5-6lbs of boost from like a A trim?

Nice set up, you will need 30# inj min I would think for a NA combo. A lot of the new blower combos has higher compression ratios so you would be fine with anyhting between 9:1 and 10.5:1. An A-trim isn't going to be enough to feed that 342ci motor.

[DemonGT]

what do you mean it wont be enough to feed it? i was just looken at possibly a small blower to just add alittle thats all...and i think the shortblock with those heads runs like 10:1 compression

[Rick 91GT]

Originally posted by DemonGT
what do you mean it wont be enough to feed it? i was just looken at possibly a small blower to just add alittle thats all...and i think the shortblock with those heads runs like 10:1 compression

The A-trim just will not flow enough air to effectivly feed that 331ci motor with AFR 185's etc...even with swapping pulley you may only see 4psi of boost. Hopefully WADS56 chimes in, he had a A-trim on his car for a brief moment, I am sure he can elaborate.

You would need a S-trim or P1SC or Novi 200 to make power with a blower.

[WADS56]

Rick is right. The A-trim will not be enough to feed it efectivly, but if you still have a stock block it will be enough to crack it. A stroker alone with heads, cam, intake, etc... will put you over the 400hp mark. Now add a blower and it will not be hard to reach over 500hp, even with the A-trim.
I was running a 347 with the combo below except for the fuel system, and the A-trim (6lbs). I had a crappy mial order custum chip and still was hitting around 128mph at the quarter. I was also blowing head gaskets about every 2 runs.

IMO there is no way the A-trim would be enough for a all out race motor with a svo block, but it is fine for your combo.