Best way to get 450hp? Gen1 350 or 5.3 Gen3

[Pro-Tour Heavy Chevy]

Okay here it goes. I have a solid 350 that is fresh with about 10k on it with mild cam, stock(ported) heads and the usual bolt-ons(Perf-RPM, headers,MSD etc.). It runs fine and it's reliable, but I'm looking for more. I was thinking of Changing the heads such as RHS Pro-torkers or Edelbrock RPM's or other and install a Hydralic-Roller Cam such as Comps XR270HR. Okay that's one way. I been bitten by the LSX bug and have acquired a 2004 5.3L From a Tahoe with about 48K on it for FREEE. It's a complete clean motor from Intake to pan and coils etc. I have a CTS-V pan already.
Now I only have the engine, no harness or ecm. I would need everything to do the conversion, plus a new cam and whatever to up the power of the 5.3L which I believe will be a more efficient and reliable powerplant.
My plan was to gather parts for the 5.3 over time and do the swap and still be able to enjoy the car with the engine I currently have, but the $ spent versus what I get in return has come into question. The Idea of an LS motor under the hood is tantalizing and could be done in the near future, but I have a good foundation to make more power with the 350. I believe I'm over thinking this and am suffering from information overload and need to get back on track one way or the other
I want to shoot for about 450hp with decent drivability

[SoCal Cruzer]

Tough Call, or is it. You can make 450 with the 350 but mileage and driveability may suffer and it will have thumpy idle, which isn't a bad thing. Heads and a roller cam will set you back close to 2K or more. So I would say drive the car as is and stock pile parts for however long it takes and put the LS in. You will have better drivability and mileage and should hit the 450hp mark with a little work (i.e. pocket-ported heads,GM hot cam, etc). You could even run the truck manifold if it will clear your hood. It runs out of steam at about 5500-5800rpm, but how much time do you keep it there. With the LS you can have your cake and eat it too for about the same as building up the 350. Hmmm.

[Mark Antrim]

As Socal Cruzer said the ls would have a roller in it. To update a gen 1 small block to a roller would be alot of extra money( I put a retrofit roller in my engine and would probably do a ls engine next time).

[alnoe]

Hi Mike

I am also looking at this same idea. I think when you add up what new parts you will need (swap headers, mounts, radiator, etc.) that by the time you are finished with the 5.3 build, it will end up being more in the long run. You can build an easy 450 HP 350-as mentioned, you will need a pretty decent sized cam, but we offer a few top end kits that can get you there for a reasonable price:

The link below will give you a few options-retro hydraulic lifters are about $400, and are the only other piece you would need, aside form a good shortblock. If you do want to do a 5.3, you can make 450-475 HP very easy with our 205 head and any one of our hydraulic rollers-pretty neat little engine.

Thanks
Al

http://www.trickflow.com/egnsearch.a...=KeywordSearch

http://www.trickflow.com/egnsearch.a...=KeywordSearch

[67Camaro RS/SS 350]

You can build 450hp without going roller, but it will be lumpy at idle. If you go FI, then that will tame it down at idle quite a bit. Going roller is good for longevity and you can run more lift without as much duration as a tappet cam. True it will cost a little more for the roller components, but before long, having an LS setup is going to be everywhere and the guys who stay with the Gen 1's are going to be rare. Why have something that everyone else has. That's why I am building a gen 1 385 roller setup.

[Pro-Tour Heavy Chevy]

The 5.3 seems that it can offer the best of both worlds. Good power, Drivabilty/reliabilty, and maybe even ,dare I say, Mileage. But there's a good argument for the 350. It's in the car already, it runs well and has a good solid foundation to build on, but will probably get too lumpy even with a rolller. I also I forgot to add if I wanted to add F/I to the 350 that could add 1500 and more to the build and that's where things start to get interesting. I mean if you want to compare apples with apples you shouldn't leave anything out, right. Thanks Alnoe for the links and some perspective. As for LS setup being commonplace I just did the Cruisin for a cure show with over 3000 cars in attendance and I was hard pressed to find LS conversions, they were there, but few and far between, and at the RT66 Show (1900 cars) and I could count them on 1 hand. One thing for sure the Gen1 isn't going anywhere.

[yellow heap]

What heads are on the ls?I'm not real hip on the ls platform-YET-That's where the ls could have a big advantage-HEADS MAKE POWER.
with the 350 450hp and REAL street ability is not a slam dunk-it can be done
I would get the best 200 cc or less head(AFR180-195 pops up) you can get if you want to keep the cam small
I would also say a 383 and 450hp is almost a slam dunk
My next motor will be a 400 or a stroked ls similar in size-tough decision indeed

[6'9"Witha69]

My 383 is 508 hp 542 ft/lbs. An Isky hyd roller, Dart 215 heads with 2.05/1.60 valves, An Eddy Perf RPM, a 1 inch open plenum spacer and a 780 cfm Holley. Rotating assembly is all SCAT w/ JE pistons. Really smooth @ idle, decent vacuum. 114 LSA on the cam.

[Pro-Tour Heavy Chevy]

The LS motor has stock heads as well as the 350. An Edelbrock Top end kit(for example) with Roller Cam can get me 410-435hp, which is close to my goal, but that could set me back 2500 or more. The 5.3L with a little head work(Texas speed) and a new cam can hit that mark, it's just the conversion parts that add up.

[1badchevelle]

what about a 5.3l carb set up it will help to keep the cost down?

[Jarcaines]

I have a 350 that puts out about 425-450 HP, but I would LOVE to upgrade to a 5.3 build like Track Rat is running. You can't get that kind of fuel millage and drivability out of a 450 HP SB. But yeah, cost and having a motor that runs has put that on the very back of the project list...

[Pro-Tour Heavy Chevy]

The cars 350 is decent and puts out about 330hp. And the 5.3 has less than 48K on it so it only needs any upgrades. I'm leaning more to just drive the car with the 350 and enjoy the car and gather parts for the LS Conversion along the way.

[tonykim]

Check out the top two combos on AFR's website (http://www.airflowresearch.com/chevy_dyno.php). The first one is a 9.5:1 355 with the comp cam 270H (which is smaller than your cam) and it makes 430 hp and 470 ft-lb.

The 2nd combo below uses Comp cam roller Part # 12-432-8 Grind # XR282HR-10 and makes 450 hp and 470 ft-lb. Also, this same roller combo is on Comp Cam's website but with less cylinder head and made only about 400 hp.(http://www.compcams.com/technical/Dy...2HR-10_001.asp)

Personally I'd do the AFR 180 head swap and with your cam you should pick up about 100-120 hp and leave the cam alone.

[Pro-Tour Heavy Chevy]

A good argument for the 350. What cam do you think I have FWIW it's 224 Duration @ .050 with 465 lift on both Intake/Exhaust with a 114 lobe separation. Nothing too special. I know heads would to tremendous things to the 350.

[70camaro406]

I agree with tonykim. The heads alone (AFR 180) will wake it up like you wouldn't believe, and with that slightly mild cam, should have a great idle with enough beans to buzz past 6000. Speaking from experience, the heads that I have (AFR 210 comp ported - 100%) are the best investment that I made for my engine...and the by far the biggest boost in hp, too.

My 406 has a pretty average bottom end...Scat crank, 5.7 rods and flat-top pistons. But I have a solid roller cam with a stud girdle, a Super Victor, and big headers, and it easily revs past 6500. You should have a wide power band in a 350 with the AFR 180's and your cam.

[Pro-Tour Heavy Chevy]

It starting to sound like a set of heads would be a good start to see what comes of it and then a Cam upgrade(Hydraulic or Hyd. Roller) if need be. That would be the quick and cheaper way, but would it be the better way. I know Head tech goes along way for even the Gen1 and even cam tech too. So does it look like I could have decent street manners and hit the mark. What about cruising mileage. The 5.3 that Steve1968LS2 built is an awesome example of the potential of the 5.3. And Damn it looks Sweet. And those Numbers. WOW!. Now back to to the 350. Set of heads and the right cam will reach those numbers, but.....

[SoCal Cruzer]

I just did a simulation using Comp Cams Camquest and used your 350 w-Edelbrock performer heads flow rates entered. And with Comps XE268H Flat tappet camshaft it came out to 459.9HP with 460.5TQ Not too shabby with a head upgrade and a cam swap. The cam is conservative too at 477/480 lift with 224/230 duration. I'll plug in the AFR 180 flow #'s and see what you can get with those heads. These are Ideal #'s but at least you get an estimate of power output

[SoCal Cruzer]

Just plugged in the #'s for the street AFR180's and it came up with 482HP/468TQ. I'm sure these numbers are optimistic, but these are pretty decent.

[camaro68]

Horsepower TV did a build on a 6.0 out of a HD truck and got 514 hp. I think they put a cam, new rocker arms, larger 92mm throttle body, upper intake, and larger fuel injectors. Plus a modified ECM.

[Pro-Tour Heavy Chevy]

And that's what got me started on the LS kick. The 5.3 without the all the smog stuff and headers puts put out something in the mid 300hp (About what I already have) So imagine the potential with a different cam a little ECM work and the install would cost about the price of a good set of heads and a Cam Swap.