Thread: 350 build up help

Tweet

If i were you, i would get nice pair vortec heads from summit racing or jegs peformance parts for $500 for a pair, which is pretty good deal.Then buy or self nice set or hypereutectic pistons with a flat top with valve notches and with a matching moly ring set. Use Lunati voodoo or Comp cams extreme energy camshfts. The voodoo cams are very good cams, they make very good power, but also have excellent street maners, and they give that awesome lobe to the idle, but its not radical to affect your idle quality.get the camshaft approximatley 262 or 268 advertised duration with about .470 or .480 lift try not get too much lift- there is limit on how lift vortec can receive. use your stock crank, but maybe put a light polish on the journals. stock rods should be fine, but keep the revs below 6500rpms. Too be on the save side, put some ARP bolt in the rods and have your local machine shop recondition them. don't go overboard on the header sizes, small chevy do like smaller headers sizes-hooker 1-5/8 is good choice. use a edelbrock or weiand intake-both very good-make sure they fit vortec heads!!! and use a edlebrock- or holley 600cfm- 650cfm is the limit otherwise your engine will be doggy. This combo will have about 9.5:1 compression and you'll be able run pump gas all day long without problems, it will also have a nice lobey idle, but not too rough where you have trouble keeping it running, and you also have vacuum to run power brakes and so on. The vortec heads will make this engine churn out over 380hp and 430ft torque with out a sweat. what ever this motor is going in, it will probably haul ass and get decent 15mpg city and 18mpg highway depending your gears. well good luck!!

Well I know I tend to look for the low buck way and that is not always best but if you can find a local library with back issues of HOT ROD magazine, take a look at this article.

HOT ROD magazine, December 1995, page 26

They got a little over 300 HP at 5000 rpm using the H.C. Master rebuild kit which comes with a performance cam. They did it for $800 in 1995, but I doubt if you could do it for much under $1500 today. In particular they reused/rebuilt the rods and I would opt for new rods along with the pistons. Also the cam they used was quite long in duration as a way to get high rpm HP and maybe the low rpm torque suffered, although they reported 295 ft. lb. at 1500 rpm which is not bad. I got suckered into this idea back when my expenses cramped my income a lot but now I wish I had put out a bit more and purchased a crate 383, although that usually requires high test gas. If you look around on the Internet you should be able to find a crate 383 for about $2000-2200.

Don Shillady
Retired Scientist/teen rodder

Well I have decided to go another way. I bought a LT1, trans, wiring harness and computer from a local salvae yard for $900. The car had around 84,xxx miles on it. I guess I will get that thing running and build a LT4 if I am not satisfied with the power. The way I see it 3 grand for motor and you still have to pump the gas pedle in the morning. LT1 fuel injected.... get r done.... Thanks for the replys guys. Kevin

Hey fellas should I invest my money in my stock heads to port them out to 190 cc intake runners and shave them down to 64 chambers or should I buy new heads? The thing is though is that I want this to be a Edelbrock Performer RPM chevy and Edelbrock does not make one as I want, I could buy one of those but then Id be putting money in them to port them out.

Originally Posted by #1firebird

Hey fellas should I invest my money in my stock heads to port them out to 190 cc intake runners and shave them down to 64 chambers or should I buy new heads? The thing is though is that I want this to be a Edelbrock Performer RPM chevy and Edelbrock does not make one as I want, I could buy one of those but then Id be putting money in them to port them out.

Why do you think you need a cylinder head that has a port volume of 190 cc?

Firebird, check out this site for a review of how SBC heads flow. When you say you might port your stock heads to 190 cc for better flow you need to tell us the head numbers that are down in between the rockers and springs near the center of the head. If the last three numbers are 883 then you have the "best of the worst" stock heads. The old 327 double-hump 461 heads had much better flow but may not have bolt hole bosses in the end for accessories. If you have the 883 heads, they probably have thin walls and cannot be enlarged much. You would be better off taking a look at stock Vortec heads or one of several aftermarket heads. The AFR heads are very good but expensive. If you are going to run a compression ratio over 10:1 as you said previously the only way you might ( ? ) beat the need for high octane gas would be to get aluminum heads like the ones on a late model Corvette. In my experience you can safely smooth out the 883 exhaust ports but the intake walls are thin and they are not going to get you much over 300 HP. I already sent you a link to Ryan's Dyno tests and in there around example 45 or so there is a dyno run for a totally modified set of GM 883 heads which does not come up to aftermarket HP numbers for other heads.

Check out: http://www.chevyhiperformance.com/te...ench_database/

I am using 883 heads with just exhaust ports smoothed and leaving the tiny 155 cc intakes alone with rough walls to maintain fuel-air mixing and good low rpm torque along with slightly better mpg. If you want HP in the 400+ Range you will have to go to higher volume intake ports but for the street maybe 190 ccs is too large and folks on this Forum tend to favor 170-180 cc port volume for an engine which is run on the street. If I were doing it over again I would buy the stock late model Vortec heads for about $600 a set. I spent $300 on rebuilding the 883 heads and another $200 to smooth the exhaust ports so for another $100 I could have had the Vortec heads. You will notice that most of the 383 crate motors have Vortec heads because they are the best breathing stock heads. Read through the flow tests in the site I give above and you will see that there is a tradeoff in that large port volume is needed for high HP as you say, but then you may get bad bog at low rpm when you need to keep the ports small enough to get good flow velocity to pack the combustion chambers and smaller port volumes will do that, so maybe 190 cc ports are too large? You need to study up more and or find a shop guy you think you can trust and let him build the engine. Remember the Farmer who said to his wife, "Martha, I don't trust anybody but me and thee, and I'm not so sure about thee either!"

Don Shillady
Retired Scientist/teen rodder

Excellent post Don

Tech1, I'm learning, but you forgot more than I know! Take your laptop to Nicauragua and keep in touch because it's going to get cold sooner than you think in Wisc.

Don Shillady
Retired Scientist/teen rodder