[MonteMan8686]

hi i am building an 86 montecarlo LS. i just recently bought a 350(not sure of casting numbers). I am looking for some tricks and cheap ways to increase horsepower. i put a set of 305 heads(354434) because i hear it increases low end power. please leave any tricks you may know. oh and i am new to building engines and such so forgive any ignorance i may show thanks

[torrey]

While the 305 heads will bump up the compression ratio, it will run out of steam pretty early; it won't pull more than around 3500-4000 rpm. I think you can get them machined for bigger valves, to get them to flow better, but if you're going to spend that much money, you might as well get a set of Vortecs and make a lot more power. I'm sure more experienced people will chime in shortly, but things such as headers, good dual exhaust, cam, converter, and especially rear end gears will really wake it up. Also a good dual-plane intake and four barrel carb.

[my87Z]

get rid of the 434 heads, the compression is not worth the loss of top end, seriously. get a set of vortec heads like these

http://cgi.ebay.com/ebaymotors/REMAN...item2559763f14

or find a set of 4416 305 HO heads they still have the small chambers which will raise your compression ratio but with these you will still have some power over 4000rpm, they should be fine on a 350 up to around 5000, after that they will fall off very quick. get a set of full length headers and a decent 2 1/4 or 2 1/2" dual exhaust, i would recomend dynomax for the mufflers. if you go with the vortec heads you will need to get a vortec patterened RPM maifold (you should be able to find one used) get a decent 650 vac sec carb, HEI performance distriutor, look for a cam with about 205-210 advanced duration (nothing higher than .460" lift) anything larger and you will have to have the valve guides ground down and get new springs, find a set of self-aligning rockers and your good to go

[Hippie]

The possible combinations are virtually endless as are the threads on here about 350 combos. Spend some time reading old threads, you'll learn a lot. That said.........

The '601 or '416 305 heads are the ones you want if you go that route.

Is your 350 a roller cam block? That would make things a lot easier. A goof "first time" performance build would be a 350 with stock 12 cc dish pistons, a set of iron L98 heads from a IROC or GTA with a 5.7 TPI engine, ZZ4 roller cam, Performer or similar intake and headers. This combo can be capable of 335HP at the flywheel on 87 Octane with good low end TQ. If you're patient and do some shopping around you can build a decent 350 pretty cheap. I picked up a good used ZZ4 cam with about 2 Hrs. of dyno time for $75 off eBay and you can often find unused crate motor takeouts for about $100. I also found a pair of decent iron L98 heads with a like new set of stock roller lifters and the retaining hardware for $75 off Craigslist and I see roller cam 350 cores all the time for $100.

'96-'99 Vortec heads are a proven power maker on mild builds but will cost you a bit more up front, require a different intake and they are limited to about .465-.470 lift (opinions vary) without some modification. The L98 heads and other '97-'95 heads have a slight difference from older heads in that the center 2 intake bolts on each side enter the head at a slightly different angle. Manifolds are available but an older intake can be easily modified by elongating the holes and making a wedge shaped washer. I think some one is actually making washers for the conversion. Both heads have 64cc chambers.

[MonteMan8686]

thank yall for the help but i really have no way to get the vortec heads right now so can i get some help based on what i do have. basically im saying i cant get new heads for the moment so what can i do to make this setup work???

[my87Z]

theres not much you're going to be able to do honestly. in a motor the heads are what allows the engine to make power, without a decent flowing head you wont be able to increase the hp much. you could still be able to go with set of full length headers and decent dual exhaust. since you say that it's a monte carlo LS then i would look into finding a similar year SS monte carlo rear, as long as you find one that came out of a car that had the 200-4R o/d auto trans then it will have 3.73's and posi, this would really be the best thing you could do.

try and save up a couple of hundred bucks and get a set of vortecs, you may even be able to call up some local junk yards to see if they have any, if so get the heads and the stock self-aligning rockers from it, then you could get another cam, lifters and pushrods. i would say that you could possibly do all this for about 600.00. only then will you actually be able to increase the hp/tq by more than 15-25.

[Landshark928]

Without replacing heads, you're left with headers, better exhaust, maybe a cam? Or Nitrous.

As said above, your heads are the limiting factor. Most other things you can do will not give you the full benefit when choked down by those heads.