have 305 NEED MORE POWER

bhw33191 · #1 10-23-2007, 07:51 PM

i have a 1983 Caprice Classic 305 and this car in general is pretty weak. Is there any cheap way to get more HP? The only thing i can think of doing that is somewhat cheap is to put in a true duel exhaust or a racing cam of some type. Is there anybody that has done either of these two things that can tell me what type of cam or exhaust they used? Even better can anyone recommend anything else i could do that would still be fairly cheap?

silicon212 · #2 10-23-2007, 07:57 PM

Niether of the above will really help. The problem is low-end - the 305 really doesn't have much. It can be made to, but a 350 can be made to make the same power for less $$$.

PeteA216 · #3 10-23-2007, 10:40 PM

Even a completely stock 350 will have a very significant difference in power and accelleration. Gears wouldn't be a bad idea either.

bhw33191 · #4 10-24-2007, 01:23 PM

Quote:

Originally Posted by silicon212

Niether of the above will really help. The problem is low-end - the 305 really doesn't have much. It can be made to, but a 350 can be made to make the same power for less $$$.

M

alright so now that im sure the 350 would make a significant difference. how much would a 350 swap cost "i'll do the labor myself" and where could i get one. Most importantly will there be a need to buy any new components "like an ecu" also?

silicon212 · #5 10-24-2007, 03:06 PM

Quote:

Originally Posted by bhw33191

M

alright so now that im sure the 350 would make a significant difference. how much would a 350 swap cost "i'll do the labor myself" and where could i get one. Most importantly will there be a need to buy any new components "like an ecu" also?

Depends on where you get a suitable used engine. If you live near an Ecology or a Pick-n-'Pull, you can get the entire engine including the belts and what the belts drive, for less than two hundred, provided you pull it.

As far as the ECM, since your engine is carbureted, don't worry about it. My police package came from the factory with a 305 in it. I installed a 350 out of another car I had, dropped it in and ran with it. Over 3 years and 60,000 miles later, the 305 ECM is still running strong. You might find a little better performance with a 305 carb ECM running on a 350 - due to the fact that the spark advance curve tables are a little more aggressive on the 305 ROM.

---

Your 1983 should have a TH700R4 in it if it's got OD, or a TH350 if it doesn't. In the case of the TH350, you don't have to worry about the 350 as the tranny will handle it just fine. With a 700R4, I'd get a suitable donor transmission from a newer car (1987-1993 TH700R4/4L60 - not 4L60E). If your car has a TH350, you might want to consider the newer TH700R4/4L60 just for the economy. If you do wind up going from a TH350 to a TH700R4, you will also need to get a suitable driveshaft and crossmember.

At one of those junkyards I mentioned, you can get the entire outfit for less than $400.

mike561 · #6 10-24-2007, 06:24 PM

I was considering doing a 350 swap eventually, being as how the 305's dont have that much power potential, but i dont want to decrease gas mileage

silicon212 · #7 10-24-2007, 06:52 PM

You can actually make a 305 go if you're willing to try aftermarket heads (such as the World Castings S/R Torquer 305 heads) and some cam and exhaust upgrades. It is, after all, a Small Block Chevrolet and it will respond to Small Block Chevrolet upgrades.

The point is, a 350 can respond to the same mods and get more power. However, a 350 is about 5% less efficient than a 305 in the same car, from an economy standpoint. This may or may not matter - in my case, the lower MPG was a tradeoff well worth it from a power standpoint.

I'm considering a compromise on my next build, however -

I'm thinking that the engine to replace the 350 in my 9C1 will be an updated, fuel injected 327. Should be about the same power-wise as the engine I have now, with the economy benefits of 23 less CID and EFI.

Added that if I came across one relatively cheap, the new (in a manner of speaking) LS-series Vortec 325 (5.3) is a screaming powerhouse in stock form and that would go over very well in my car.

PeteA216 · #8 10-24-2007, 10:08 PM

I like the idea of vortec, I've tossed that idea around in my head a few times.... could aftermarket (or even stock) vortec heads be installed onto a a '92 block and successfully use the same 1992 if I could find a manifold to fit the votec head geometry TBI? Also how do vortec heads do with a supercharger... I'm still kind of hanging onto the whole "blown" engine idea for the future.

silicon212 · #9 10-24-2007, 10:34 PM

Two different types of Vortec engines here - the one I am referring to is the LS1-based Gen III engine, the one you're thinking of is a Gen I or standard small block. Those cylinder heads will bolt right on any old small block, the only thing you'd have to worry about is the intake. However, there is a good aftermarket for intakes for those heads - you can even get a carb intake for them that allows you to retain your standard ECM setup. A full-bore Vortec 5.7 will require its OBDII PCM.

PeteA216 · #10 10-25-2007, 10:19 AM

Would vortec heads with a stock OBD1 ECM and stock (or even modified) TBI even be worth it? How much of a power difference could there really be?

silicon212 · #11 10-25-2007, 10:53 AM

The issue is whether or not they make an L03/L05 style intake that works with Vortec heads. If they do, then you're home free. I do know they make a Vortec intake that works with the carb and distributor that I have, such that I could put a set of Vortecs on my own car if I was so inclined (and I just might be).

The Vortec head generally has the same flow characteristics as the cast iron LT1 head, but can be used on older small blocks (whereas the LT1 head only fits LT1 or L99 blocks). How much power you gain from them is subjective - many factors so I can't tell you how much you will pick up, but you will pick up top end.

PeteA216 · #12 10-25-2007, 11:54 AM

Well, I guess thats something I will have to research when the time comes. Until then, a bone stock TBI 4 bolt 350 it is. Hopefully the dual exhaust and headers will at least give me a few more ft/lbs.

mike561 · #13 10-25-2007, 12:32 PM

maybe a dumb question, but is it possible to put a supercharger on these engines?

PeteA216 · #14 10-25-2007, 03:33 PM

Of course, but if you leave the engine stock it will drastically shorten it's life.

j cAT · #15 10-27-2007, 07:43 PM

Quote:

Originally Posted by bhw33191

i have a 1983 Caprice Classic 305 and this car in general is pretty weak. Is there any cheap way to get more HP? The only thing i can think of doing that is somewhat cheap is to put in a true duel exhaust or a racing cam of some type. Is there anybody that has done either of these two things that can tell me what type of cam or exhaust they used? Even better can anyone recommend anything else i could do that would still be fairly cheap?

this is a good engine for this vehicle wt. but the exhaust and air intake is restricted. with cat removed and dual exhaust installed at a custom exhaust shop with cherry mufflers and a larger air intake on the carb with ram air then adjust the transmission detent cable for less downshifting on the highway you will soon realize that you need rear stabilizer bars. also make sure that the fuel pump and small gas fiter in the carb is replaced. this has been a problem rust in fuel restricting gas flow....

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