[1969ChevelleMalibuSS]

Hi I have a 350 out of a 71 vette that is going into my 69 Chevelle the engine is a l-48 so mostly all stock 8.5/1compression but I read 4 speed cars came with a little higher compression like 8.9 or so which this engine was originally mated to an m20 but what I have done is installed a comp cams xe268 and a torker intake with an edelbrock 600 I am wondering if I will make more than the stock 270 horse rating hopefully around 300ish?


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[Lilracr]

The only way you will know true compression is to CC all the parts and hand calculate it. I have seen motors that claim 8.5:1 measure out in the 7.9:1 range from the factory. I would not worry as much about that unless you are willing to pull the heads to check it am possibly mill the heads or change the pistons for more compression.

The one thing you can do for much better overall power is to change out that torker intake for a good dual plane design.

Forget about horsepower and focus on overall engine torque and figure out the perfect timing and fuel the motor likes.

 

[1969ChevelleMalibuSS]

I am looking at a prefomer or prefomer rpm air gap not sure which to choose but for the time being I will try to get the engine in the car and running this weekend


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[overdriv]

Like he said, focus on a dual plane intake for your engine. And a good 600CFM carb like a Q-jet or Edelbrock.

 

[1969ChevelleMalibuSS]

I have an eddy 600 not a big fan of it though had it on another car an arent most q-jets 750s at least that's what I have heard


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[jeff swisher]

if the secondary air door opens all the way on a Qjet then you will have either 750 or 800 cfm
BUT:::: GM was sneaky..and different cars got a different total opening on that air door.
Take a look at one of the first turbo V6's that GM made..
Buddy of mine had one..it had a Qjet carb..rating was 450 cfm in a book he showed me..could be 460cfm....memory escapes me..

I look down the primaries and i see the 800cfm carb was used.
I open the secondary air valve door.....it barely opens 1/2 way...

GM trickery.....wonder what that car would have done if that door opened further?????

 

[70-SS454]

I'd try the PERformer... 250 Tops..

 

[67RAT]

had a 70 350,9 to 1,194 heads,factory intake,quadrajet,point dist,factory manifolds

it was rated 300 hp factory--

 

[67RAT]

Like he said, focus on a dual plane intake for your engine. And a good 600CFM carb like a Q-jet or Edelbrock.

or holley 650 spread bore!!!!!

 

[1969ChevelleMalibuSS]

had a 70 350,9 to 1,194 heads,factory intake,quadrajet,point dist,factory manifolds

it was rated 300 hp factory--

Was the 300 horse rating pretty close? I'm trying to shoot for 300 but can't really raise my compression w/o changing the heads


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[67RAT]

Hi I have a 350 out of a 71 vette that is going into my 69 Chevelle the engine is a l-48 so mostly all stock 8.5/1compression but I read 4 speed cars came with a little higher compression like 8.9 or so which this engine was originally mated to an m20 but what I have done is installed a comp cams xe268 and a torker intake with an edelbrock 600 I am wondering if I will make more than the stock 270 horse rating hopefully around 300ish?


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get a set of 2.02 chevy heads 64 cc chambers,slap a 480something lift/284 duration cam in her,daul plane intake,600-650 holley,and a set of cheapo headers,and you will have a good motor with 350 hp or so...can do all this with the block in the car-and some 373 gears-
well there goes your budget!!!!! probly do it for 1500 bucks minus the gear change-ebay-jegs,summit,
summit sells 2.02 heads prepaired by dart for a good price per pair-they will up the comp ratio ,your heads are most likely 78 cc chambers-and it will still do pump gas-been there done that and that old 350 would rev to 7200rpm,make power to bout 6800 or so--

if you do this the torker will work also,in my opinion dual plains are for motors making power to 5500 or so-the above will go beyond that rpm for sure......

don't go over 650 with the carb,a 650 will run muuuuuch cleaner on your motor....as compaired to a 750-800 or so..

how many times did I say OR SO????

just my lame 2 cents

 

[67RAT]

Was the 300 horse rating pretty close? I'm trying to shoot for 300 but can't really raise my compression w/o changing the heads


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BEST THING I DID TO MY 350,NOW THIS WAS BACK IN 1983,WAS CHANGE THE HEADS,you will not regret the money spent....

summits cast 2.02 heads are the best bang for the buck,you could go afr,brodix,so on,but to me what you want is just a cheap strong street motor..... go cast 2.02
summits have the holes on either end for ps,alt-and so on...

 

[67RAT]

Was the 300 horse rating pretty close? I'm trying to shoot for 300 but can't really raise my compression w/o changing the heads


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oh hell I don't know,was a 350 from a 70 impala-300 hp,ran good all day long-then I started messing with it-than it ran really good..

remember engines are air pumps,make it breath for cheap and it will be a stout little motor...

 

[1969ChevelleMalibuSS]

Thanks might end up doing this ur 2cents aren't lame just a lil on the expensive side for a high school budget but my cam is 480 lift but wayy less duration so I have to change tht too wasn't real happy with the idle quality although that shouldn't matter


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[67RAT]

Thanks might end up doing this ur 2cents aren't lame just a lil on the expensive side for a high school budget but my cam is 480 lift but wayy less duration so I have to change tht too wasn't real happy with the idle quality although that shouldn't matter


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keep that cam in her,its broken in,and you wont take the risk of wiping the cam with heavy springs on new heads

ask anyone here,heads mean a lot-check out the summit ones youll like the price-I was on the same boat as you with my 350 build,20 years old,didnt have much money,saved saved saved,got it going on over time-well worth it-

 

[67RAT]

Thanks might end up doing this ur 2cents aren't lame just a lil on the expensive side for a high school budget but my cam is 480 lift but wayy less duration so I have to change tht too wasn't real happy with the idle quality although that shouldn't matter


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what gears ya got?------also,auto or 4 speed????

bobh

 

[1969ChevelleMalibuSS]

A slip an slide power glide ;( I have an m20 that i plan on using when I can afford to put it in (I love driving 4 speeds) and its a 10blt 3.36 non posi


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[67RAT]

A slip an slide power glide ;( I have an m20 that i plan on using when I can afford to put it in (I love driving 4 speeds) and its a 10blt 3.36 non posi


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that has to work for now, good luck with the build,keep me posted, pm me anytime!!!!

 

[1969ChevelleMalibuSS]

Thanks sure will should be running this Sunday or monday


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[1969ChevelleMalibuSS]

Just wanted to say thanks for everyone's input have been driving my baby for the past 3-4 weeks and love it she feels slow off the line with the slip n slide powerglide so that will be the first to be replaced then a carb and intake and ignition


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