Team G

Ok,c so currently I have an h/c LS6 in my 98 Z28. It has AFR205's on it with a custom grind cam that is .585/.585. Can't remember he other cam specs off hand.

I'm looking to build a budget motor. Thinking about picking up an iron 6.0L short block, punching it like 30 over, going through it, keeping the stock crank, throwing in a set of nice forged pistons, and maybe a nice set of rods if the budget allows them. This should, if I've been told right get me about a 377ci short block on the cheap that will more than handle the occasional 200hp dose of nitrous that I like to use ;-)

The question is, what should I top that short block of with? Should I keep my AFR 205 cathedral port heads and go up to a .600ish lift cam and save some coin to use else where?

Or should I ditch the AFR'S, grab a set of either stock or possibly cnc ported LS3'S, and go north of a .600 lift cam.

I really like that new holley efi tunnel ram looking intake and am thinking i'd like to try that out. How ever, I don't hink they produce a version that works with cathedral port heads yet:-( I'm not married to that idea, the intake I can figure out. Was planning on going with a single plane intake, elbow, and a big throttle body for a while now till I saw that new holley intake. Intake I can figure out later.

The main thing is I need to figure out what heads and cam to go with on that short block I described. The plan for the short block, I am married to, so other suggestions on the bottom end aren't needed, thanks!

Rise of the Phoenix

iTrader: (27)

I think the AFR 205's would work just fine for you. I would sell the cam you have and get a custom grind cam that will complement your total setup and goals. But, you could also sell the AFR heads (should have no problem getting at least $1,500 for them) and buy some LS3 heads and get them ported. If you did go that route, with selling the AFR heads, you should about break even. If it were me, since I already have the AFR heads, I'd go with them. They are a proven head and will work well with you setup.

NVR_SPDS

iTrader: (39)

Stick with the AFRs. They are a very solid performing head, and since you already have them, theres no money spent.

You could have Tony@AFR touch them up, or fully port them and youd see even more gains with them.

Get a custom grind cam (Id go through Tony for this as well) to match the new motor. The AFRs will handle a big shot better IMHO, since they have such a thick deck as well.

Team G

i was under the impression that the rectangular port heads out flowed the cathedral port heads? I mean even out flowing my afrs? Stock afr 205 to stock LS3, ported to ported, and so on. This is why i was thinking about switching. Plus with the rectangular port heads, seems i might have more intake options too. Like that new holly i mentioned earlier

Was thinking if that were the case, I could sell my heads, and pick up a set of cnc'ed ls3's and be ahead of the game maybe?

I've had my car for ever. Kinda got out of playing with it for a long time. All the ls3 and newer stuff i just really don't know about, and trying to catch up on.

bayer-z28

iTrader: (14)

yes yes and yes... ^ AFR 205's are some damn good heads.

redtan

iTrader: (5)

As good as the AFR205s are, I think a nicely ported LS3 with a matching LS3 intake will run circles around a 205 and LS6 intake.

If you can get the AFRs ported quite a bit and add in a FAST then do that, otherwise I would go with the LS3s.

Also, that shortblock combo will net you 370ci

mikh338

iTrader: (16)

ye i agree with your comment on making it a 370

bayer-z28

iTrader: (14)

And there was an interesting tech article in the recent GMHTP on cathedral vs rectangular port heads. Cathedrals produce great low end power. Port velocity may suffer on a smaller bore with rect port head though, but produce great higher rpm power.

redtan

iTrader: (5)

That is true, I guess I was going by what's going to make more power and I still think a ported LS3 will. GMHTP did a comparo between the LS3s and AFR225s and the LS3s made more power and torque also under the curve. The AFR205s will make more torque being smaller, but will get taken up dop.

So it all depends on what he's doing with the car. If it's a mild street car with great all around power then yeah keep the AFRs. If it's more of a race/strip car then the LS3s will perform better with more power up top.

Team G

Thats what I was originally told too. But a couple people I know who did this same motor claim it's a 377.

At 370, I would still be pretty happy. That more than half way to a 383, and for a bout a 5th of the price I can allways add but more juice to more than make up for the 13 less cubes


Like I said earlier, It ISN'T a DD anymore. Don't so much care too, too much about street manners anymore. Although I still want to be able to drive it without too many head aches

Getting ready to swap out the 1st/2nd gear set in my TH400 For the 2.97/1.57 set soon. So low end torque won't really be a problem. I can allways stick more gear in the rear end too to get it moving down low if I have too. Plus lets remember, I spray everything! Have two kits on the car now. Not to mention, with a 3600-4000 stall converter (3600 now, have to get it restalled and considering 4k) low rpm torque isn't really a factor! I would actually prefer more mid to high rpm torque and hp!

My main interest is to make as much power as possible, for as little as possible on that short block i am building. Not because I don't have the money, but because I am taking this up as kind of a challenge. Many people i know spend a **** ton of money paying others to buld thier ****. I have allways enjoyed beating up on them with my low budget stuff that i generally (not allways) have put together myself. Just makes it that much sweeter, lmao!

Team G

ttt

So how about some ideas and discussion?

Mike Morris

iTrader: (55)

Keep the AFRs for sure.

Suzaku

iTrader: (3)

Why not get AFR 230s?

Team G

I'm not trying to spend a bunch of extra money. Merely trying to maximise what my new motor will do with the current investment of the heads I have (maybe plus a bit of massaging), or selling them to cover the cost of he investment on a set of rectangular port heads and porting on them.

I just really thought that the rectangular heads would out flow my afr 205's. If I hd the afr 225's I wouldn't have even possed the question and just stick with them.
But I have the smaller ones, and am loking o improve on them!

I think I will call afr, and maybe a couple other shops and see what they have to say?

...Todd

bww3588

iTrader: (49)

I don't know what the afr's are going for but I would imagine if you sold them for a set of Ls3's, you could probably break even, even after buying the offset rockers, stands, intake and tb.

You can sell your ls6 intake for twice what ls3 intakes are going for.

Also, the stock untouched ls3 heads will more than support a good cammed 370 and leave you plenty of room to grow if you go larger cubes.

Just keep in mind, switching to an ls3 top end is more than just heads and intake.

You will need a new, cable driven 4 bolt tb, rails, injectors or injector adapters to use your ls1 style injectors.

Other than that, it's pretty straight forward.

For a cam, I recommend calling Geoff at EPS. He just hooked me up with a cam for my 370 build just exactly what you are planning on doing.

TransAmcoupe98

iTrader: (10)

AFR 205's on a 377 c.i. would have some crazy good throttle response and down low power. However, if it were me, I'd send them to tony and have him work his magic and port them to a 225. You'll need more air to fill those cubes. I def keep them, AFR is the ****.

mikh338

iTrader: (16)

very good info here, sounds like we are going the same path. what cam are you running with this setup?

bww3588

iTrader: (49)

230/242 113

Team G

Whats the advertised lift? is it a nitrous cam?

And if you built a 370 like what I am working on, would you mind sharing what parts and pieces you went with? I am very curious!

I am starting to think maybe I should just hang on to my afrs, have them ported, get a nice came to match them, the cubes, and and edelbrock single plane intake set up with the elow and throttle body like i was planning on before.

bww3588

iTrader: (49)

Do not get the elbow. if you going with a single plane, go with a 4150 style tb. Elbows kill flow and power.

I went with stock ls3 heads and intake. That cam and full bolt on's. Geoff at EPS did not tell me the exact lift over the phone, but I am sure it's around .600 on both sides.

He is confident I will see 450+ at the wheels with the stock heads and intake.

I went with wiseco pistons with valve reliefs for the larger ls3 valves. Should put me right at 11:1 after checking ptv and milling accordingly.

I went with stock stuff for now, but next winter, I'll probably tear it down, stroke it, have the heads cnc'd and do a fast 102 combo.