Ive heard over and over again that 347's are unreliable and that they are only good for 20-30 until they need to be torn back down and rebuilt... if that. There is a guy that I know who has been building a 347 for the past 3 years. He just didnt have enough money to finish the whole project. He wants to know if I would like to buy the whole car for 4,000. Rebuilt rear, 5 spd. and the motor only has 6,000. I probally wont get it because of financial reasons (not really broke but just looking for Suzuki GSX R750) but I was just wondering how unreliable 347's really are and what you can do to make them more reliable. If I did ever get it would be just a weekend warrior.

 

Once upon a time 347's were know to have oiling problems due to somthing to do with the rings. Search on google for them and you will find alot of info. Supposedly certain compaines now have kits that have elimated the old problems with building a 347, some agree that they are better now, some dont.

 

IMO, let him keep it, unless u buy it and mark it up 5 hundred and sell it for a nice profit like my uncle does.

 

Unreliable is not a good term....they are reliable. They just don't have the longevity that smaller strokers do. I have seen 347's go 60-70K before needing a freshening up...while a 331 can go far past that. Granted that is with little to mild abuse...anything that is hammered on repeatedly every weekend is not going to last that long

 

isnt he better off with a 408W or a 306 (bored .030 over 302, not a stroker)? they take alot of constant abuse right?

 

A 408 is 351W based stroker.....that opens up a whole new bag of worms...different accessory brackets, oil pan, etc.

There is rarely a need to bore the 302 roller blocks...if not needed it is a waste of time and money since you are buying new pistons. I have seen the majority of even high mileage roller 302's just need pattern honing and new rings and bearings...anything from 87-92 have forged TRW pistons in them already. Many guys have used stock bottom ends with Turbos and gotten amazing numbers out of them.

As far as abuse....that is a relative term depending on what kind of abuse we are talking about

 

As far as abuse....that is a relative term depending on what kind of abuse we are talking about


????lifting the foot off the gas???? whats that hey paul. whats the widest tire that will fit on the rear of a 92 lx? i have the 16x7 pony's

 

I wouldn't recommend going over a 245/50 16 on the back with those rims...larger "can" fit but are too big and adversly affect handling. If you change wheels you can get a larger tire out back...I ran 275/40 17's on the back of my '88 LX(17X9 wheels).

 

thanks for all the help guys... I was at the Englishtown swap meet (in New Jersey) today and seen a really nice 88 GT 5.0. 77k original miles, mild body repair, power everything, tinted windows, auto (want to go c4 anyway) imaculate interior, runs strong. 2400! Im putting my car on ebay very soon and Im going to try to get it because I wanted to do a 408 stroker... I can do the motor but than I will be broke and wont be able to finish the car. It takes a while for reality to set in . Dont know how long hes going to be hanging onto it though. Maybe Ill get lucky. Who knows...

 

i saw that car yesterday, where the frig were u, i was in NJ all weekend, i saw paul senior at OCC today though............. :bang: did u see uncles truck yesterday in the show? did u see the blue 86 that only needed paint?? 2900obo
their was a mint 88 gt, white with white interior, amazing, the turbines were unscared too, 12k original miles, 5.0 with 5 speed

 

oil problems with a 347 stem from long rod 347 combos, the piston pin is placed up into to the oil control ring and requires a spacer to support the rings, but still allows oil to seep past the ring, short rod combos have an actual ringland in the piston that eliminates this problem. If R/S ratios are a major concern then dont bother with a 347, I would say especially where you might run high static and dynamic compression ratios and oil can contribute to detonation problems (in the case of a long rod 347).

I hear (and it makes sense, but hearsay has to be taken with a grain of salt) that gapless compression rings also help control oil problems in engines which are prone to them (ie; a long rod 347 with low tension rings).

Aside from that, there is the rod to stroke ratio of the combo itself. Long rod champions are quick to point out that the R/S ratio in a 347 is absmally low and will sap power and increase cylinder wear due to increased side loading and this is true, but there are plenty of factory engines that have the same or worse R/S ratios. IIRC pontiac 455s chief among them.

However this is also a function of piston speed (yes 347s also have higher piston speeds) and in the context of a street engine that spends most of its time at relatively low engine speeds its not a critical factor.

On the plus side short R/S ratio engines are a bit more forgiving when it comes to parts selection as they tend to tolerate larger heads and cams a bit better and tend to be a bit more volumetrically effcient in an apples to apples comparison (two identical displacements wih identical equipment the only difference being R/S ratio).

The bottom line is application and as always money, If your looking for a light weight engine combo that is relatively cheap to build using off the shelf parts (due to cost constraints), then a 347 is a good option. Especially if you like to race like you play poker. 347's and 302's are hard to tell apart.

 

Yea Doug... H actually had it for sale for 3000 and I was walking by it with my friend and I said to my friend... "yea I MIGHT give him 2400 for it" and the dude jumped out of the seat and was like Ill take 2400 right now. I want that car... Did u like it ? Needed some minor body work but I had him start it and it souded really good. To tell you no trust it just had a flowmaster catback and it souded better than my car with my full exhaust.

 

now which car r u talking about? i was in love with that faded 86 and that white vert.

u see that one 94 or 95 GT, it was silver with 95 R wheels which didnt match the paint color, but it had a intake and GT40 heads and exhaust and stuff, didnt look like a GT40 intake to me, i think he needed his eyes examined, BTW i went to new york city and i loved it, it is amazing except for the sewer.........

 

except for the sewer?.... and back to topic... anyone got any more info...?
And by the way... I didnt see any of them other Mustangs. I was on the side w/ mostly tables the whole time and I didnt even know that the other side was open and than by the time that we got there I was drained. I didnt even look at the cars on the track. The 88 that I seen looked like the 86' hood with the one thick black stripe. It was almost bone stock and it was just a faded red paint. Im guessing that it was original.

 

oic, i saw all those cars in the swap meet on saturday.
9the sewer drains in NYC stink horribly, steam pours out of them)

 

That's because you were a visitor....try spending some time working there and paying your own way for everything....then you would hate it.

 

fof course, the prices are outrageous, my uncle is down their about 3-4 times a week for work and he still oves it he drove/drives down their too

 

I may be a little behind hear but i thought I would let you know that there was a guy on another mustang site that said he had heard of numerous problems with the Coast High Performance 347's. That was just his opinion and this was about a year ago so who knows they may have improved by now but I just thought I would let you know.

 

Well I really appreciate the heads up. I dont think I would ever buy a 347 anyway. I hear of too many problems with 347's with their oiling and everything in between. I rather stick with a 331. They last longer anyway and I have some money but not enough to be replacing motors every 30-40k. I like to drive my cars rough (even though ive never got a chance with my mustang but my intrepid is ok for now lol) also and I hear that 347's are not good street cars sooooo I dont think that I will be getting one any time soon. It was just that the guy had it and it was dirt cheap so I was def. considering but the whole car is already gone. It sold 4 days just from word of mouth.