I have a little 383 w/ an xfi 280 cam. I had edelbrock e/tec 200cc heads and a HSR on it two days ago. I sold the intake and decided to take the heads off and sell them too. (still for sell in the classified section) This setup did well for me, but as we all do, I got bored and decided to upgrade to a set of afr comps and a miniram.(still looking for one at a reasonable price) I was wondering what you all think the power gains will be. I know there are many variable here, but I'm not going to hold any one to it if they are a little off. Here are some of the fine details.

The motor has about 10,000 miles on it. It's internally balance, cast steel crank, stock rods out of a vortech block,(not that that matters)and hyper pistons that give it around 10-10.25to1 comp. The cylinders hold good comp. Around 180. The cam is a comp xfi 230/236 .576/570 at 114lsa(i think the lsa is right) Its got 1.6-1 roller rockers, 1 5/8 headers into a 3in catback. T56 trans and 342 gears. Obviosly it will have a 58mm tb and enough fuel.

So what do you think? This is really just a fun build thread, I don't want a bunch of argueing about he said she said bs. Just positive critisicm. Oh and sorry about all spelling errors.

 

I think you will want to look for 1 3/4 primary headers! That intake/head combo will flow some serious air, I think your cam is suited for a nice 6500 rpm redline and the Miniram will definitely like that. Sounds like you will pick up some ponies up top and lose a tad on the bottom end of things. I hope you have prior dyno #'s that would be cool to see how much you gain!

 

+1
1.75" primary headers are a MUST. There will still be a good bit more to gain by switching to long-tubes and duals.

 

Thanks for the replies. I have intensions to get some 1 3/4 long tubes and a 4in mufflex exaust in the future. In the mean time I'll just use a cut out at the track. I'm expecting around 425 at the wheels. I ordered my heads with bigger valve springs so it would be easier to switch to a s/r setup later. I'm still looking for a miniram, 58 tb, 30-36lb injectors, nice set of perimeter bolt v/c, 7/16 1.6 rockers, hardened pushrods, underdrive pullies, etc. To say the least it will be a little while till I get it all. Heads won't even be here for another 4 weeks.I'm about to pull my hair out waiting. My other setup ran damn good with the etec heads and hsr. I'm anxious to see what 45 more cfm head flow and the miniram will do to the power band of this thing. I plan on doing a little ls1 hunting for sure.

 

You will see a good gain with those heads. Flow alone will net some good power. But those heads have the proper springs that will work well with that cam's lobes. i dont know what springs you had on the Etec's but if they are anythign less than the AFR 8019 springs, you probably were not getting the most out of that cam.

 

What did you run for hp or et's before?

I have your intended set-up, except I have a LT1 converted intake(basically same as the mini-ram but for half the price)
I had a flat tappet cam, not roller.

X2 for the 1 3/4 headers, mine were a restriction until I got exhaust cut-outs

Ets are below

 

You will need 1 3/4 headers just to cover the AFR exhaust port. 1 5/8 leaves a step in the exhaust path and that will hurt flow

 

Yeah I hear you on the 1 3/4 headers. I need to find a set with GOOD ground clearence. Maybe the ed quay ones or something. My etecs had 1 3/4 ports as well so I took a grinder and squared the existing header flange and matched it to the gasket as best as possible. I assure you these are as good as 1 5/8 can flow. My y pipe has a straight piece after the merge that is beggin for a cut out. My car made about 390hp and went 11.90's with mt et streets. I beleave I have found a good miniram canndidate and should have the heads soon. I'm going to have a new tune done as soon as I get it running. I hope to get around 450whp out of this thing soon. I'm spending around 4,000 on it right now so it better fly. My old setup would roast the tires about half way through third gear with 3.42s. I assure you I'll get plenty of pics of this thing as it comes together. And ofcoarse some vids of this thing tearing into some h/c ls1 cars

 

The heads are good enough for it, but cam may need to be bigger to approach 450whp. Maybe try the massive 1206 port miniram and a xfi 292 or bigger

 

I considered going with the 292 cam but I've decided I'm not going to switch cams unless I go s/r. And thats not going to be untill I build another shortblock. Tpis doesnt offer the 1206 port anymore so I'll have to have a smaller miniram ported to match.

 

Got an email today.... Heads should be here friday!!!!!

A buddy of mine is going to sell me his nitrous express fogger system and I think it would be a nice addition to my project. It's the under the injector style. Good to 500hp I believe. I would go 125-150. It also comes with a purge solenoid, no bottle though. Great price. What do you think

 

SWEET!

 

A buddy of mine is selling his nitrous express fogger system. He got it a couple years ago but never ran it. It's the under the injector stlye. I think it would make a nice power adder for my project. I'd run it with 125-150 jets. It comes with a purge solenoid also but no bottle. I can get a great deal on it. What do you think?

 

<---------nitrous junkie.

I like the under the injector kits. Basically eliminates manifold puddling issues.

 

Special Delivery!!!!!

Well my heads showed up today. I'm going to be honest, I've been wondering if these heads could possibly be worth the 2000 bucks I spent on them.... As soon as they showed up I went and grabbed one of the etec heads for comparrison and ripped into the box like a kid on christmas morning. All I can say is WOW! I had been thinking since these heads have similar sized ports and runner volume that there wouldn't be much difference, WRONG. The fully cnc'd AFRs are totally different. All the transitions are much smoother and you can tell the are built beefier. In the Edelbrocks defence they are a much more economic option. They made good power but these comp port AFRs are one an entirely different level. I'm sure Edelbrock offers a cnc'd head and they would be closer but damn I can't wait to see what these will do.

I have been thinking about using a larger rocker arm with these heads. The 280 cam is 576-570 lift with 1.6 rockers. I have seen some 1.65 and even 1.7 rockers online. I am thinking of using the scorpion 1.65 intake 1.70 exaust of maybe 1.60in 1.65ex. That way I would get more exaust lift for better nitrous use. What do you guys think. Here are some pics

 

couple more just for luck.

 

purdy

 

leave the rocker at 1.6. I dont think those XFI lobes will like 1.7's. It would start to get hard to control the lifters on the lobe even with those springs on those heads. They make special lobes for high rocker ratios, the XFI was designed for 1.6's so i'd keep it there.

I'd love to see over .600 lift on those heads for sure, but I dont think its a good idea on those XFI lobes.

You doing a miniram or single plane?

 

I've pretty much decided to go with a miniram. Jerami at AFR insist the miniram will make good power and the single plane will have low end problems. I would consider the pro flow xt if edelbrock would give me any flow numbers but they are pretty tight lipped. The biggest limiting factor will be finding a manifold that can be ported to the 1206 gasket. Actually the afr heads aren't exactly the same as the 1206 gasket. They have 3/8 radiases and are a little bit narrower. I already had the HSR and it was a good intake but I want something a little different. Who knows maybe I'll get a 177 blower and plumb it for fuel injection.lol

 

Good point on the lobes, my father said the same thing.

 

I dont know what they base their data on at AFR, but miniram and singleplane would see the SAME low end power. Runner lengths are the longer on the singleplane so it may make more low end. I dont see a big difference in the miniram vs single plane except for the air distribution issue.

You will not have a low end issue with that car, trust me IF you liked your old setup, this should really make you smile.

My lazy 9 to 1 compression 401 motor with a single plane and a very loose converter and 2.73 gears had no problems on the low end...drove around just fine with good feel.