'70 Sierra Grande - Engine upgrade

[Randy B]

looking to replace my current stock 350ci/290hp with more power, something in the range of 350-400 hp. want something that will bolt-in exisiting framework & mounts and not computerized (FI okay). I have a TH400 tranny and 344 Posi, any suggestions of best/simpliest retrofit ? thx.

[OlSmokey]

Someone can correct me if I'm wrong, but you can get a pretty cool 327, with a custom cam and upgraded pistons and put out some pretty serious horsepower. And as long as you just use it as a daily driver and not a racer, you'll see an mpg increase from the 350 you have. I'm saving up to get a 327

[MARKDTN]

I am a bit confused by non-computer FI OK? Are you saying mechanical fuel injection but not electronic?

There have been a number of builds of 350 with Vortec heads and Tuned-Port that get into the 350+ HP range. Scoggin-Dickey sells the intake. TPI parts are dirt cheap now. This would be a bolt-in swap as far as mounts, hoses, and exhaust.

[Davidf]

If it was me and I had a 350 block, then I would look into a 383 stroker kit in combination with modern (i.e. Vortec) heads/intake and leave it carbureted. By the time you go the FI route, you might as well drop in a LSx.

That's what I plan to do when the 350 in my '71 finally gives up the ghost.

For example:
http://www.ebay.com/itm/383-ASSEMBLY...t_24842wt_1362

[Randy B]

electronic FI is ok, what I don't want is a computer controlled engine which I believe all of the LS3's are ?? sorry for any confusion on my part. thx.

[hugger6933]

A 350 with the later block like from the trucks 96-99, they have roller camshafts in them making a aftermarket roller upgrade less expensive[but you tell the cam people so the right kind of roller can be bought] The Vortec heads are awesome so I think you would get real close with a Vortec motor[350] and change out the cam[and springs and other needed stuff]and have the heads touched just a little and you will def be on the lower end of what your wanting with a good dual plane intake[RPM air gap] and and good carb and hot ignition. Now with the later blocks you will give up the ability to have mech fuel pump.

[crazyjeenyus]

It all depends on how much $$$ you can spend.

A potentially less costly option is to use what you already have as a base, and replace the worn out parts.

Theres not a whole lot different between a 290hp 350 and a 350hp 350. Could be just the pistons & heads.

I assuming your engine has 76cc combustion chambered heads....these alone drop the hp rating substantially.

If I wanted 350+ hp and I had a stock sbc, I would have the block decked, get higher compression pistons, aluminum heads from jegs or summit (about $1,000), comp cam xe262h or xe274h, edelbrock performer rpm intake, and a 570 or 600 holley.

This shouldn't be much more than $2,500 depending on machining costs in your area, and with this combo you definitely wouldn't be left wanting in the hp department.

If you want stock sbc heads, get some 64cc power packs from a 283, but by the time you have the valves opened up and the port work done you'll have more than paid for some decent jegs aluminum heads.

....my 2 cents

[crazyjeenyus]

I just noticed you are from Calgary. Check out kijiji, I saw a 383 kit on there for $2,500. Its got the rotating assembly, some nice DART aluminum heads, and an aluminum intake.

http://www.kijiji.ca/v-engines-and-e...ationFlag=true

You'd be north of 400hp with this setup.

[j_cst_10]

I have a dyno proven recipe (because I put my car on a chassis dyno). It's fairly cheap and makes 440HP and 440ft-lbs at 6,000rpm at the crank with the correction factor. I've got the Hp and tq curves somewhere from it.

I built this engine 13 years ago with a scat cast crank, factory truck rods with ARP bolts, and hypereutectic pistons - nothing fancy at all about that. Or buy a bottom end pre assembled.

383 bottom end roughly 9.5:1 compression ratio
Dart Iron eagle heads with 2.05 Intake/1.60 exhaust
Comp hydraulic roller 238/242 at .050" with .525ish lift
Edelbrock air gap
750 holley
38 degrees of total timing

[MARKDTN]

Originally Posted by Randy B

electronic FI is ok, what I don't want is a computer controlled engine which I believe all of the LS3's are ?? sorry for any confusion on my part. thx.

Me today, LS is the way to go. If you just can't see yourself doing that then TPI is a very viable option.

Tuned Port fuel injection is a real shot on the arm for a stockish small block. It was used on F-bodies from 85-92 and Corvettes 85-91. The visual appeal is awesome. The LT1s came after, but they do not use stock accessories so they are not as easy to use. I have done a number of TPI swaps and the difference is impressive. One of the beautiful things about a Tuned-Port is low end torque. That is where they really shine. They are not high RPM engines without a lot of work. Mileage is also much improved over a similar carb engine. I have said before, I pulled a stock 4-bolt 350 out of my '83 K20. It has a 700R4 and 3.42 gears. It always got about 14 mpg city and 18 highway. I replaced it with a stone stock TPI 350 from a '91 Corvette. I now get like 17+ city and 20+ highway. The difference pulling a load is also impressive. With the carb engine and a load I was always on the gas when I hit a hill. With the new one it just hits the hill and starts pulling with just a little more pressure on the pedal. A neat thing about using a stock system is that parts are available at any parts store nationwide. Anyway, if you want 350 reliable HP and good economy but don't want an LS, you may consider TPI.