Nick Crosby

I would like to get 200 hp,out of 305 block. Block is an 80-84 305. Trying to find the right combo. Any suggestions would be great. I wouldn't mind trying to get 300 but I think that would be out of my price range.

mcquigg

A stock carb'd 305 is rated at 190, with a few changes such exhaust headers, ignition, smog, etc. you will have your 200.

200 isn't much and a waste of time, your better off with more horse power, but if your going to invest in mods to the engine get rid of the 305 for a 350.

JamesC

iTrader: (5)

IIRC, my LG4 was originally rated at 155, the L69 at 190.

JamesC

big hammer

200 isn't really an issue at all lol

Fast355

iTrader: (2)

You can get 300+ HP out of a 305 with relative ease, no need to get a 350.

Get you a set of 059 vortec 305 heads and a matching vortec intake, a set of headers and matching Y-pipe and a good catback exhaust. Then put a small cam in it like a Comp XE262.

firechicken83

is this also changing gear ratio? cause im not looking to get the horsepower and then blow my rearend.

Fast355

iTrader: (2)

Gear ratio won't change a thing its the crappy 7.5" thats the problem. I have seen a good running 2.8/Automatic take out a 7.5". I am setting up a ~280 hp L30 305 in am Astro van and IIRC it has the weak 7.5" rear.

Rainmaster

I have around 230hp (dynos 185rwhp with an auto trans) coming from my 305. The only things I've done to it are a full 3" exhaust with shorty headers, L69 dual snorkel, and a Comp XE268H-10 cam. Next thing on the list is a set of Trick Flow Super 23 175 heads which should help push me pretty close to 300hp at the flywheel.

Fast355

iTrader: (2)

That is a lot of $$$$ on a head that is really no better on a 305 than an 059 L30 305 Vortec head that has the Alex Spring/Retainer setup for .550" lift. I am anticipating on my Lunati 268 cammed L30 putting down about 250-255 RWHP through the 4L60E and 7.5" 10-bolt in the Astro. That's about 310 HP at the crank.

dmccain

iTrader: (2)

Fast you have just about got me considering a similar build. Sounds like an awesome street engine. Just about what I wanted out of a 350 build.

Rainmaster

It's true that it is a lot of money, but the Trick Flows are aluminum which will help against detonation as well as shave off a few pounds. They also have potential for further worked to squeeze out more performance than the vortecs have to offer.

Rainmaster

If you want to build up a streetable 305 without going bonkers, this is a good read: http://www.superchevy.com/how-to/pro...-engine-build/

Fast355

iTrader: (2)

Unless you are putting flat top pistons on a zero decked block with tight quench the compression ratio is not going to be high enough to have to really worry about detonation, especially with that 268 cam lowering your dynamic compression ratio substantially. I milled a set of 059s down to 53cc, used a 1.56 compression height flat top piston with 4 reliefs for a total of 6cc dish, zero decked the block and ran a .038" compressed 3.8" bore head gasket. With the XE274 cam the engine ran without detonation at 10.6:1 on iron heads on 93 octane with 32* total advance at 2,800 rpm. Dynamic compression ratio even with that much cam was about 8.6:1. With a 3,000 rpm converter it pulled strong from a stop and everywhere on the powerband.

Fast355

iTrader: (2)

I will let you know what I think of it when I finish the build and get it running. I am hopefully I will get my ring set by the end of the week so that I can put the engine togather Saturday evening after work and get the thing installed on Sunday. I am piecing together all the accessory drive setup and modifying the V6 wiring harness to run the V8. Then I have to get the PCM reflashed to a 5.0L G1500 Express vin# to tell the PCM it is running a 305 rather than a 4.3.