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? help with Chevy 350 build ?

3K views 19 replies 4 participants last post by  ap72 
#1 ·
First off I am new to the site and I have been doing some searchs and there is a lot of good information on here. What I have going on is I have a Chevy 350 in my 68 firebird. This winter I want to pull it ouy and do some upgrades to it. Current set up is bored to 355 edelbrock 600 carb edelbrock performer rpm intake edelbrock performer heads not sure on the pistons I know there noy forged and I believe around 8.5 compression with all stock lower end. Cam is a crane 4 wheel drive cam not sure on specs . I bought this engine from my buddy out of his lifted truck just to get me by for a while it runs good but it was built to be a daily driver I'm wanting something more radical. Without spending crazy money how can I get some good HP numbers out of this thing. I have been thinkin along the lines of a new carb, bigger cam. And going high comp as I can and still run on 91. Also been thinking bout strokin it to 383 ill be runnin a turbo 350 and either 3.73 gears or 4.10 gears. What I would really like would be a low 13 car maybe 12 just not sure if that would be possible without spendin a ton of money thanks alot
 
#2 ·
If it were me,I would just get some TRW forged ft pistons(2256F)just for leaning on it alittle harder ;) They are a good piston and not expensive at all. I then maybe would get a Comp cams 280 or Edelbrock rpm cam-had good luck with both.ARP rod bolts and main studs.This will make for a stout bottom end as long as you not doing over 6000-6500 rpm very often or throwing more than a small Nitrous shot at it.If you are just building a good sounding and running street car,This would do nicely and fairly cheap. :thumbup: Just my 2 cents.
 
#3 ·
just get a mini blower kit and leave the rest as is for now. The build you have sound sto be a prime boost canidate and some of the minikits go for around $1500- which is actually less than it would cost to tear the engine down and rebuild it to higher compression, stroker, etc.
 
#4 ·
where can I get the mini blowers at for around 1500? I priced a Eagle rotating assembly with srp pistons and with my heads would give me 11 to 1 compression. It is 1200 for that, 300 for the new carb and i figure somewhere around 200 for a cam. I think that would be a pretty hard running engine. I want something that sounds good but im wanting to go out on the track and be able to lay down some decent numbers
thanks
 
#5 ·
Bare in mind that the setup needs to match. That is heads, compression, exhaust, cam, intake, carb, gears, and stall.

Are you prepared to go through that expense and major changes to the car? If you build the engine up and go with 4.11 gears and 3000+ stall it will have major effects as a the daily driver. Just to let you know what you are getting into.

A mini blower or N02 is a good option if you want to keep your current setup and just add more hp and torque.

It seems that you already have a good set of heads and intake manifold. However, the compression is a little low. So pistons, new gaskets, cam, valve springs, stall, bigger carb, headers, and gear change would be required if you want to make power with a bigger cam. The cost adds up quickly.

You don't need forged pistons on the street, in fact, I don't recommend them. You can make plenty of power with a good set of cast pistons (hypers). Forged pistons rattle around in the bores when cold which makes them noisy and causes wear.

I'm liking the mini blower idea with a cam change. Run 7 or 8 psi of boost and use a msd boost retard with a mild blower cam. I thinking 475 hp and 525ftlbs of torque. And you can run a 3.08 gear and stock stall if you want to keep the daily driver setup. I would invest in a limited slip center section.

I bet you can find a used mini blower for 1500.00 complete with carb. This of course assumes your current engine is in good shape (good oil pressure, no smoke, ect). 1500 is cheap with you start adding up the cost for making power with a big cam.
 
#7 ·
I misquoted the cost of a new kit- its a little over 2 G's

http://store.summitracing.com/partd...part=WND-6512-1&N=700+400053+115&autoview=sku

As stated though you can find a used kit for less than a grand- or nitrous which is $500 or so for a 150 shot on a carb. :mwink:

Or the self fabbed turbo setup- which most people can do with some back yard ingenuity and about $1000.

All of these are cost effective and will supply more power than your drivetrain should recieve... So look into buyig a built tranny next and a 12 bolt.
 
#8 ·
this is a street car but it does not come out often. With 11 to 1 would that require some sort of race gas. Or at least a mix of 91 and 110? I like the idea of the blower and it sounds like that can get me just as much power and doing the stroker. i would like to be somewhere in the mid 400's on horsepower. The motor now doesnt even have 2000 miles on it. It runs great just want more power.
thanks guys
 
#9 ·
I would go with a supercharger kit, and maybe a cam depending on what you're currently running- it may not be that bad to use the one you have now though. And a supercharger with a healthy cam will put you at 400HP without even trying- I would look into maybe going with a Vortec head setup before you buy the supercharger though, as you can keep from buying two intakes. The Vortecs will really help your engine flow and 500HP wouldn't be hard.
 
#11 ·
you can run 11:1 cr with pump gas if the cam is big enough and has enough stall and gear.


The difference with a blower is the engine would make the same power but with a much smaller cam. And a mild cam will have a smooth idle and you can run a stock stall and gear. Plus the low speed toque would be twice as much. So you save some cash on gears and stall and it makes a much nicer street car. Plus you could use the engine you have since it is new and has 8.5:1 cr.

Performer heads are better than vortecs. I'm sure ap72 missed that in your setup.
 
#12 ·
i really would like to do a big cam just because of the sound. I Know a blower would be better for driving but if I was going to do something for drivability I think I would just go with a ls1, 4l 80e and then I would have fuel injection and over drive. I want something that has a lot of rump. I want people to know its coming :)
 
#13 ·
you can have a good "rump" if you want it, but that rump is just wasted power and fuel. Some of the bet street machines have a near stock idle quality. To get that rumble with a blower you can simpley narrow your LSA to 106 on a cam and run about 10 degrees more exhaust duration than intake. something with about 218/228 @.050" with a 106 LSA and a blower would give you a nasty sounding idle and an indescribable amount of mid-range torque.

Be warned though, you will loose about 25% of your precious MPG's. And yes, I overlooked your edel heads- sorry about that.

a lot of people pick a cam for sound, and there's nothing wrong with that, however the best sounding and the best performing cam are two different things.
 
#16 ·
I'm just an engineer, but I probably spend more of my money on cars than I should. And while it is not like going to walmart and picking up a box of shells a blower is a very cost concious approach for this guy. He has a solid short block and wants good street power. he could go out and buy new heads, rebuild the bottom end, get a enw valve train and end up with a 11:1 semi-race street engine, or for half the price he can make the same power only more reliabley and with more torque... A mini-blower is perfect for this situation.


As for the carb question- yes you can reuse your old carb but you will need to retune it, I recomend reading up on it, asking questions, and trying to do it yourself. It takes more time the first go around, but if you want to claim being a hotrodder I believe you should have dirt under your finger nails.
 
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