I`ve never had the chance to ride in one and I was wondering how the stock 1970 LS5 454 performs at the track and such. All of my chevelle experience is 64-65 chevelles running small blocks. This is my first big block car. Thanks.

My 70 SS454 motor is built to LS5 specs,other than the cam,intake,and headers..runs consistant low 13's and a best of 12.99 with 2.73 gear and a TH400
LS5's have a small dome piston(.095 tall) and closed chamber heads with 2.06/1.72 valves and the same cam as the 350HP/396

Thanks. My chevelle has been sitting for who know how long and I`m sure the motor needs to be rebuilt. I probably will add a performance cam and maybe a little port/polish on another set of heads I have. I was just wondering how the LS5 performed. What cam are you running? Thanks.

A '70 spec LS5 was rated 360HP in the Chevelle but 390HP in the Vette. I personally drove a '70 454/390 automatic Vette to 150MPH (bone stock). I could have buried the speedo if I wanted to.

Back to finish. You have to decide what you want to do with the car and the motor. A 454 to LS5 specs is a good all around performing motor. A lot of torque right when you want it and enough performance to be respectable, all depends on how much cam you throw at it and what trans/gear combo you run.

thanks for the replys guys. i might end up rebuilding it back to stock since it sounds like the LS5 is a pretty decent performer. i have`nt checked the numbers to see if they match the vin but the last 3 letters decodes to a 70 LS5 W/MT which this car had a 4spd originally.

GRN69CHV, I`m not sure on the rearend gear ratio. The car doesn`t have a rearend at all so I`m working on getting one so I can bring the car home and get started on it. It has a auto tranny in it now but I`m putting a 4spd back in although I don`t know if it will be a M20 or M21, I can get either one. I was wanting to build the motor mostly for street driving but it would have to run at least high 12`s. My last chevelle with a 327 ran low 12`s so a bigblock car has to run high 12`s at the very least. Thanks again for the replys.

For street driving and for a high 12 rear ratio, I would suggest 373's. The 373's will keep the RPM at a decent level on the street and still offer a decent level of off the line performance.
Just my $.02
Chris

Herck, with a torquey BB, 3.31's are fine, imho...

Best of both worlds, decent rpm on the highway and you can still turn a mean tire...

pdq67

I was thinking of going with the 3.73 gears and a M21 4spd. 3.31 gears would be ok too but I`ve heard they don`t make them anymore. I think I`m going to step the cam up a little bit though. I do want a little lope at idle so maybe a 280 cam or something close. Thanks again for the info. It helps having other people`s opinions, especially if they have been there, done that. Thanks again,

Back to the cam...Chris runs a "near perfect" stock replacement the Lunati A7 ( aka Ultradyne 280/288), it has just a freckle of lope at idle ( 17+ Hg of vacuum I'd think), and it makes superb power. Look no further for a cam than the A7.

No BS valvtrain noise like some of the competitors cams either. Ain't bashing, just stating a fact. Framer threw an XE grind into his 325hp 396, which is a good idea in theory.

I'm NOT kidding when I tell you that my 427 with a Crane solid cam lashed tight, was QUIETER than the hydraulic.

Now, in many cases that won't matter a lick, but in Framer's case, since the car is close to original and very correct, a quiet valvetrain is preferred.

Not to mention the SLAMMING of valves closed on orignal iron seats,( hence the tickety sonics of some of the "high energy" grinds ) with no inserts.

If the car had some rear gear ( 3.50 +), you *might* consider opening the seats up for bigger valves in your heads.

Otherwise, careful engine assembly of good quality parts will yield a winner! Nothing "trick" required. ( but a more modern cam than the 1970 version )

427L88, thanks for the tip on the cam. I`ll check Lunati`s site to see if I can find it. Ii`m probably going to go with 3.73 gears and I have a second set of heads so I can add biger valves and maybe even a little gasket match and bowl work and not worrie abour ruining the stock original heads. Thanks again.

Gene, could`nt find the cam anywhere. do you know the lift and duration? where can i find it? Thanks.

Circa 1981 or so , Vic this guy who used to work where I work at bot a stock 1970 Chevelle LS5 , TH400 with 3.73's.... for $2500.00 :eek: Oh those were the days...

Anyhoo I got to co pilot in this several times...this car was all origional except for tires , shocks and brakes....I cant remember how many miles on it ...

This car was a total Jeckel and Hyde car...idled great with just a nice rumble out of the stock exh .. This car was one of the best cars ever for doing burnouts... as long as you stayed in the throttle it would spin the tires... Was it quick ? NO...
there was absoutly no middle ground... you either drove it sedatley and it was very docile and driveable.... but no matter what you did if you got after it , it slipped the tires.... For the way the car ran my impression was that the 3.73's were simply too low... it needed something more like Pdq said , some 3.31's would have been perfect.Driveing with the replacement F70-14's that were 25.5 in tall on the freeway turning over 3200 RPM on the freeways really wasnt that much fun either.... You could literly watch the gas gage go down.

I dont belive he ever ran it at Fremont but if I were to take a guess it would have run low 15's @ around 103 MPH with the stock tires.... screaming in protrest 2 thirds of the way.... Lord knows what that car would have done with some decient tires.

My buddy bought a new '70 Chevelle SS 454 LS-5 back then. It had a Turbo-Hydro and, I'm pretty sure, 3.31 posi. He never modified it at all. I accompanied him once to an 1/8 mile strip where he ran 9 second times. Can't remember if they were low, mid, or high 9's. It was pretty even between it and my slightly modified L-78 Nova when we ran 'em off on the road and mine was a low-mid 14 sec car at the time. His was Forest Green with white stripes and cowl induction. In '73 he traded it in on a new Pinto wagon due to the gas crunch. A sad day indeed.

The cam specs for the Lunati A7 are 221/231 @ .050 12 LSA .525/.550 advertised 280/288

Anthony {or should we call you Tony - you are a paison - no?).

A 454LS5 is literally any 454 engine combo with large oval port heads and a mild flat tappet hydraulic cam with CR ranging from 8.5 to 10.25 as porduced from the factory. Rebuild the motor and keep the CR at least 9.5 and add a modern cam with .050 dur @ 222 - 228 with a lobe separation of 110 or 112 for a smoother idle and you will wind up with a very strong, reliable street performer that should fit the intent that you are describing.

Thanks for the replys guys. You`ve given me alot of info to think about. I originally wanted to hotrod it but since I found out it may be the original motor, I don`t know what to do now. I finally got rid of my 70 chevy p/u project today so now as soon as I find rear lower control arms and rear springs, I can bring it home and get started on it. Thanks again.

Von, traded for a pinto? What was he drinking? Not even a good Ford, what a mistake. Pinto is probably a bunch of beer cans now or in my neighbors yard, who has about four of them. None run.

Hey it wasn't just any ordinary Pinto. It was a loaded yellow wagon with the woodgrain on the sides. ;) In '73 you couldn't give musclecars away. I sold my like new 30k mile '70 Nova L-78 in '73 for $1800 and had a hard time doing it. If we'd have only known the future then.

Remember those TV ads to justify the price gouging and the gas rationing. "The US is running out of oil". In retrospect, it was a all a well orchestrated front to justify spending the next several decades in the Middle East.

I am still waiting for the economics of alcohol derived fuels. Funny how we can race cars on alcohol, but they can't seem to get large scale alcohol to the buying public. Kind of a long shot but could you imagine being able to drive your 12.5 to 13.5 /1 motor up to a pump and fill it with alcohol derived fuel. Oh Yeah!

I would have put a straight six in the car, changed to 2.73 gears, and I'll bet it would get better mileage than a Pinto. Then years later the V8 could have been reinstalled.

IMO the LS5 was one of the best street motors of its day. The oval port head is a good streethead, and the crank/rods/block are pretty beefy. Put a intake, modern cam and set of headers and free flowing exhaust and 12s should be no problem (if it hooks). Head work, a little more agressive cam and matching converter/gears(3.73) and low 12s are within reach. I think GRN69CHV combo would make an excellent street motor and 3.31s would match it well.

Chris Corwel proved that you can make an LS5 run 12.99 while pulling a 2.56 rear cog. I mean, in a 3800 lbs Chevelle, that's performance man!

" Overdrive? Overdrive? I don't need no stinking overdrive!"

Thanks Gene smile.gif graemlins/thumbsup.gif
3945 lbs for the record..including myself and a half tank of gas

4,010# if I was driving it.

4020# with me in the seat! :eek:

Between the two of us, better take out the 3.31's and throw some 3.55's in there to make up for it, maybe a set of alum heads and a glass hood also!

With all that weight, maybe convert the car to English Drive and get the weight over the right side of the car!