I've had both and I prefer the Dart Iron Eagles as they have a much better exhaust port out of the box than the Sportsmen II's. Generally they're only about $50 more than the Sportsmen II's but $750 is less than I've found them for.

I definitely noticed a performance difference on my 406 by changing heads.

Jody

 

With the II's try and get a bigger valve size. They came with 2.05 and 2.08's. My 383 loves the 05's. When ported and polished they run great.

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Mark

1992 Firebird 355/Six Speed (Soon to be LT1)
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
"Speed KILLS, so drive a FORD and live forever!"
http://personal.lig.bellsouth.net/~racer383/

Member of the "unwanted" 3rd Gen group.

 

they have a good reputation, but if you look at the flow numbers they are good, but aren't spectacular. As was said before, the exhaust port could use a little work. Of course, my flow numbers are a year or two old and the castings might be different now.

 

I have to agree that the iron eagles are a better design

The exhaust ports are way better.
Just my opinion but I think you may want to look into some AFR heads.(air flow research)
they have the best flow #'s out of the box.

 

The trick flow 23 degree heads run about $850 or so from summit...they have a little better flow numbers than the darts...plus they are aluminum (less weight). Any of these heads will give you at least 50 hp over the 76cc 2.02's your running now...and that cam will like the extra compression from the smaller chambers. I think that with any of these heads and a bit of tuning 13.5's can be easily reached.

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova

 

well we ordered them they should be hear in 7 days where are these heads going to help most you think top end? or low end? or all the way threw thats what im hoping for so u think these heads should knock off 7 tenths in the 1/4 mile i hope so bye bye new camaros if they do.

 

they should show good improvements most everywhere over stock. The big 200cc runner may lose you a little bottom end though.

 

how much will they hurt my take off right now my numbers
60ft-1.9405 thats good huh for a automatic that only runs a 14.39\
1/8- is 9.1 at 74
1/4- is 14.39 at 94
I was hoping to get 100 mph out of these heads is that out of the question u think??

 

Thats a pretty good 60' time...you should see power gains everywhere, especially above 3000 rpms or so. I dont think 100mph in the 1/4 will be too difficult

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova

 

Camaro79,
are you shifting or you put in drive...motor souds like it should be faster than a 14.3????

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My '68 Camaro
Doug G.
68 Camaro
406 ci.

 

yeh i shift it around 5300 hundred thats what i was thinking every one keeps telling me a 406 with that setup should be in the 13s right now

 

Well a TH400 takes about 50 extra horses to run over a th350. I'd say have a reputable shop build you a good TH350. Do a search, there's something that needs to be hardened in em but I can't remember. I had mine done for $500 total and it chirps the tires shifting 1st to 2nd. I can get one for like $300 though but I chose to go to a reputable shop and someone I know. The tranny guy said it would wear it out a little sooner since it shifts stiff but I don't care since they're so cheap to rebuild. I think a 12 bolt takes extra horses to spin as well. You really only need the 400 and 12 bolt if your running some serious power like 500+ or if your having trouble burning up trannies and diffs. I ain't no expert though so take what I say with a grain of salt.

 

Camaro70tx,
rev that puppy up to 58-6000, you'll see a jump. i shift at 5800 with a 280 comp.cam(.486i/e)and she loves the rpms.

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My '68 Camaro
Doug G.
68 Camaro
406 ci.

 

If you move to a TH350, have a hardended sprag put in.

But with the new heads you should see a difference.

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and Hughes 3000 stall.Powertrax NoSlip Locker

 

Hey doug how long are your rods in your 406 small block are they 5.7 cause im not sure what mine are mabey 5.5 cause my motor couldnt rev 5800 if it wanted to i would have to show u a picture of it scattered at the track if i reved it that high lol

 

the short rod will rev just as high as a long rod ,it just put a LOT more stress on the piston skirts.if the motor wont rev anymore it'll one of many things; weak valve springs,heads too small,cam too small,bad exghaust system,just to name some of the bigger problems it could be. i just freshened my 408 and you can definately tell the short rods put alot of stress on the piston,they were scuffed pretty good on the skirts,but they are forged and i have a tendency of not letting it warm up before i get on it,which is a big no no (with forged pistons).
the air flow research would have been the best choice(195cc) for the street. these heads are AWSOME! the sportsman II are great IF they have at least a pocket pocket porting done. the exghaust side will pick up dramaticly! don't forget to drill the steam holes in the new heads or you'll have cooling problems. i hope it screams for ya!

 

don't go with a 350 tranny,you can make the inside bullet proof ,but the case WILL crack if your motor is making 430 lbs of torque or more. this is of corse talking about slicks hooking on the track,if your not going to hook up you have nothing to worry about. the faster the trans shifts(shift kits) the longer it will last! the reason is because the clutches have less time to slip. the u-joints and rearend will take a beating though with a shift kit,but who cares its all in fun! go with a 400 it doesn't take an extra 50 h.p. to turn it over a 350 ,maybe 15 h.p.. the extra strength is WELL worth it!!!!

 

I think the sportsman II heads canbe made to work very well, with mild porting especially in the exhaust port. I run a car with a 350 chevy engine that has some of the same parts as your car has 1 5/8 headers 750 carb. For a trans I use a glide,the car has never been run in the 1/4 just the 1/8 my best 60ft was a 1.50 my best et was a 7.04 at 97 mph this package is in a 86 camaro and man this ride rocks . by the way there is NO Nos on this car, and I owe a great deal of this performance to the sportsman II heads. I know their are better heads out there but for the money you are paying for this set sounds like a good buy to me. oh that 7.04 in the 1/8 equals about a 11.0's in the 1/4 mile, aint bad.

 

I have guys here that run over 550+ ft. lbs. of torque to TH350's, and they haven't had any problems with cases.Several high 10 to low 11 second cars with 468BB and NOS, and not one case yet. If they are done correctly, they will last quit some time.

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383 Speed-O-Motive stroker kit with Holley 750DP, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and Hughes 3000 stall.Powertrax NoSlip Locker

 

yeh i kinda wish we would have used a turbo 350 instead of turbo 400 but i have burned up 2 turbo 350s one was my fault it had a stall and we took off the cooler

 

i'm glad these people haven't had any broken 350 THs ,but from what i'ne seen,heard,and read i wouldn't want to take a chance with my $500-$900. the 400 is proven to be near bullet proof and will take more punishment than the 350. i've got a 350 behind my 440 lbs small block,hope it holds for a while in the 4x4. it will be beefed up.
i'm not trying to be a prick,but if the internals are built right how does that affect the strength of the case.i would like to know or have some hints so i can do this to my tranny before i go through it,thanks.

[This message has been edited by sldhd (edited 05-04-2001).]

 

The case breaks just after the internals shrapnel and lock up...its not pretty

There used to be a guy running around here in a 85 chevy truck with a supposedly well built th350 behind a nasty 468bb...4200 pounds and high 11's on slicks...completely shredded the th350 after 3 passes...it may just have been the way it was built, I dont know, but I would bet that vehicle weight and brute torque had a lot to do with it. Heck, I just put a fresh th350 in my truck last year after shredding the old one with my little ol' 355...of course there was no telling how many miles was already on it...it was ugly though...filled a big coffee can up with shrapnel, so I had a hardened sprag race and a few other internal mods done to the new one.
By the way, I wouldnt worry about the trans...I remember reading somewhere years ago that it takes 40hp to turn a th350 and 60hp to turn a th400...there are easier and cheaper ways of getting that 20hp back.

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova

 

yes, I do have the 5.7 rods...if there's a next time 6"rods and AFR195's...if money permitts.

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My '68 Camaro
Doug G.
68 Camaro
406 ci.