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More horsepower


Tom Carter

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So I am sure everyone asks this question at one time or another. I am running a stock lower 350 block. I currently have the edelbrock performer intake as well as the performer cam. The engine runs well and I have no complaints. The problem is I am wanting more power. I drive the vehicle when I can and to be honest I feel like the Silverado has more acceleration than the Monte Carlo. I don't want to go crazy to the point of a crazy idle or vacuum concerns. Just want more than what is there now.  I don't want to do anything to the lower parts of the block. Change to the cam to something more aggressive and maybe the intake if necessary. I like the Edelbrock carb that I currently using which is the 1906 650. I have been looking at the top engine kits online from Jegs and Summit racing. My head is starting to swim with the numbers and specs at this point. The problem  is I don't know what I want. Is a mid range cam better for street driving? It looks like the low end cams aren't going to change what I have to much so I don't want to waste me time and money. I realize what I am saying is very indecisive. Of course any advise is appreciated. 

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Just out of curiosity, what are you running for rear gears ????

If you're using 2.73 in a 10 bolt, no amount of horsepower is going to make your Monte go quicker. (Faster, yes. But only on the highway) 

Plus, what transmission set up do you have ?? Is it a "factory" th350 ?? The torque converter may be robbing you as well.

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the rear end is a 2.73 10 bolt. the tranny is a turbo 400. I have been kicking around putting in a 700r4 and 3:55 gears. I just don't want to make the vehicle a gas hog on longer trips. I am not looking to build a track car, just improve my situation. I was looking at the edelbrock rpm series. rpm cam and intake, maybe the heads. just don't know if that will be ok on my stock lower block.

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New heads will be really hard on a fifty year old lower end. If you’re going to go in that far, pull the engine and at least have the lower end refreshed. If it was rebuilt at some point you may be ok. 

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I've been working through the same process with mine. ('70)

The 350 is set up with a similar Edelbrock kit (1405 series carb)

I personally went with the 200r4 transmission..... Easier to switch than the 700 and has a wider gear separation. 

Still have the 10 bolt/2.73 rear end. It's fantastic on the highway.

 1750 rpm at about 60 mph, and when I step into it with the engine the way it is, She'll grab 2nd gear and take off like a rocket !!

I'm planning to put a 12 bolt/3.31 rear end in this fall, should make it more "streetable".... The 2.73 just doesn't twist up fast enough off the light.

But with the 0.67 to 1 overdrive, the highway mileage shouldn't suffer to much. These "newer" transmissions are actually nice in the gas consumption department. ;)

 

70 monte.jpg

lha10.jpg

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I did pull the engine and did do a complete overhaul about five or six years ago. I wanted to change the cam then. I told myself that if I found anything that looked even remotely out of the ordinary I was going to go to the performer rpm series. Of course the cam looked good. I have a hard time spending money to replace good parts. Of course I'm kicking my self now...most likely I'll keep it somewhere just in case. Had my heads sent out and freshen then too. 

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Heads and a big roller cam will net some gains, but that rear gear is really holding you back. Swapping to a 3.42 gear ratio would make a world of difference. I have 4.10's in mine but highway cruising is not exactly efficient 😆

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I do drive my on the highway a lot. I was doing some research while at work and I believe I may go with the Edelbrock rpm cam and intake. I like the 1906 carb currently so I want to try and stay with that. Perhaps spring will show me some rear end gears. Any one know if I change to 3:08 or so without changing the carrier in the rear differential. I haven't done much with the rear end so changing the bearings and seals is probably a good idea anyway. 

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Yes, changing to a 3.08 gear requires a "type 3" carrier. (3.08-3.73) And depending on the differential, (8.2"), it may just be easier to go to the 12 bolt. 8.2" parts are getting hard to find.

If you've got the 8.5"/8.6", you'll have better luck finding parts.

I've heard some good things about Edelbrock's carb bodied fuel injection systems.... Any thoughts ??

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A deeper gear will make the car more responsive at all RPM, went from 3.31s to 3.73s last winter and it woke my car up.  Only downside as people posted above is the reduced mileage. If you do change it over it would be a good time to look into a truetrac differential for improved traction. 

 

I second the roller cam comment above. The rollers allow much more aggressive ramps which typically means more power. When you spec out a cam make sure whatever springs youre using have enough open pressure to close that valve back up. 

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i swapped rear ends took out 411 posi put in original open rear end with 256/273 gears for some road trips. it has the acceleration of a wet sponge now. gears will wake it up. im thinking about a gear vendor overdrive to go with the posi rear end so i can have best of both worlds

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Tom, you've seen my car,2004R overdrive transmission,3:42 rear axle ratio,tall tires 275/60/15,  420hp Vic edlebrock build( circa1992)355cu.in. with the Brawler 750 carb and O/D at 70 mph , just at 2,150 rpm I getting 16.5 mpg ,no joke!! Lots of power , 10.2 compression ,68cc heads .If I did things again (BBC427 next), I'm a fan of the edlebrock heads and cam upgrades. With your carb.it will work fine. I'd invest in some 3/4 length headers also. You can wrap them to keep the heat down. If your going with the overdrive transmission,2,200 stall converter and 3:73 ratio will make it a nice street/ highway car. With my BBC I will be running4:10 gears and Turbo 350 transmission, with 2,400 stall. That way at 65mph , turn around 2,500 rpm's .I know, lots of numbers, but it's a good combination.post-259-0-61935100-1474727657_thumb.jpg

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I have been looking at the Edelbrock rpm cylinder heads too. They aren't that expensive and I really like the idea that they have been matched with the cam and intake. I haven't started the rear end research yet but it's itching at my brain when closing my eyes. I think I need to start playing the lottery...

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You can rebuild your rear end for alot less than buying heads, a cam, intake and all the gaskets. Changing to like a 3.31 or a 3.55 would seriously wake up the car. 3.31s would be better if you like driving on the highway like you said above. How much power is the RPM kit supposed to make over the Performer kit?

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Do they advertise any torque estimates? Having torque is probably what you'll feel more often than not unless youre spending alot of time above 4000 rpm. So building something to push our 4000 lb bricks out of the gate is probably better than trying to make a 7000 rpm screamer. That way itll really pull when you add a deeper gear. 

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I started looking at stage 3 posi carriers. My brain is starting to leak I think. I have never opened the rear differential on my car. I don't know if its a 8.2 or 8.5. I know its a 10 bolt. Assuming its the 8.2 the posi carriers doesn't seem outrageous.  changing to a stage 3 and not going posi doesn't seem right. I just cant make up my mind on which gears to go with. I do drive highway a lot so I don't want the engine screaming at 70mph. I was thinking 3:08 or something like that. Maybe even 3:55 but I am worried going that high. It maybe a few years before going with the overdrive tranny. after the rear end and the engine upgrades I am going to need to recoup a little. What is everyone's thoughts?

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