Hello,
At the moment I have a 350 sb with a TH 400 transmission,
if I switch to a 455, will I need to change the torque converter,

regards, Cus

 

You can use the same converter but now is your chance to improve performance buy purchasing a quality converter with a stall speed matched to your vehicle weight, gear ratio, engine cam and performance goals. A well chosen converter from a reputable company like Continental or Coan is a wise investment.

 

The easy answer is no, it will work just fine.
Dave I think he's working on a Delta or Regency so not really sure he's looking for a performance converter. I also think that he's in Australia.

 

First, the stall speed of a given converter depends on engine torque. The same converter behind a 455 will stall at a higher speed than it will behind a 350.

Second, people loose a lot of sleep over "high stall" converters. As Dave and others point out, the converter stall speed needs to be matched to the engine torque, car weight, gearing, and intended use. There is NO reason whatsoever to install a higher stall converter in a street cruiser that will never see the drag strip. The reality is that you want the LOWEST stall speed that works for the way you drive that car.

 

The best thing to do is call around to the torque convertor manufacturers tech line and tell them what your engine specs are(have your cam pn available), what trans, and gearing. They will make a recommendation for what will work with your setup and intended use.

 

Thanks for those good replies.
Yes, the car will be a street cruiser so I don't need anything too wild,
just slightly off topic, I think its going to be a bit of a drama getting a 455 from the states,
the odd one pops up here in Australia, here is one on Ebay
http://www.ebay.com.au/itm/OLDSMOBIL...25.m3641.l6368
is silly money, but may be able to haggle, seems to be a bit of a pig, with some
cylinders down, hopefully no cracked heads, but seems to be a good combination
"F" block & "C" heads, interested in your thoughts,


regards, Cus

 

Agreed with everything else in Joe's post, but I'm going to disagree with the sentence quoted.
If by "cruiser" you mean a car with a mild cam, sure. But perhaps the #1 mistake people make with their cars is putting too much cam into it and then not installing a higher-stall converter. In those cases, the higher-stall converter is exactly what will MAKE the car a nice cruiser. The right converter can greatly improve a hot engine's manners -- at idle, coming off idle, and yes, at WOT.

 

Exactly why I stated that this is the opportunity to improve the car & upgrade the converter.

 

I love how he says "C performance heads". All BBO heads except W30 from 67-69 were C heads. This came out of a big car (exhaust manifolds and trans tail shaft tell the tail on that). If it's anywhere near you it might not be a terrible idea to make an offer on it. It's already down there and you can freshen it up easily enough.
The compression issues could be sticky rings, heads that need to be redone, or even bad head gaskets.
If it were me I wouldn't give more than $500 for that combo here because its all core stuff, but being down there you're looking at a premium for it due to location and availability. Offer him $1500 AUD and see what he says. I have a feeling that is less that what shipping would be on just an engine from the states. It can't hurt and the worst that can happen is he says no.

 

I noticed the ad says 1971-1974 (which really sounded odd) but with C heads and what appears to be a divorced choke, I would say it's a '68-'69 engine.

 

I thought the "C" performance heads was a good one too, "Very Special!!!"
At least they are honest showing the compression etc. As you guys know I can get
an engine well under $1000 in the States, costs me $700 + AUD to get it home, plus
you can get cranky quarantine officers who insist on cleaning, which can cost $$$$$,
ask me how I know. This mob have had that engine & another Buick engine for some
time, I don't need the tranny, & also I'm not in a mad rush, so might offer them $1000
or so & see what happens. It's about 6 hours from me, bit of a drive, but have relo's there, so could combine the trip. I thought the heads might not match the block, thought they might be later than '69,
Cus

 

The VIN stamp on the block will tell the tale on that one, but I suspect that that combination is original to itself. It looks rather unmolested to me.

As far as the trans goes, it can never hurt to have a spare for something like that, just in case. Especially when you are dealing with a "foreign" car with somewhat rare parts.