dodgeitclevelan

I have an 85 camaro Iroc Z with a 305 HO With a t5 tranny. I blew both head gaskets a while ago and figured this would give me an excuse to put some goodies in there while I am at it. I found a good deal on a pair of 140102187 twirly heads. From what I read these head a decent if you want some low end torque. While I am at I thought I would replace the cam with a comp cam with a XE262H. I also bought some hooker 2460 shortie headers. After I get the car running I will get a muffler shop to run new pipe and give me true duals with 2.5" pipe and a cat delete. I am also deleting the egr the smog pump and the A.I.R system. My goal is to get produce 300 ft. pounds of torque at the crank. Will these mods produce this with the head I just got or will it be better to use the original heads? My other question is should I use the 1.5 or the 1.6 roller rockers? I have tried to do research on this but I keep getting different answers. And where can I can i fond roller rockers for a 5/16 stud? Oh btw this car is a weekend driver if that matters at all. I wanted to thank for the answers on advance.

Night rider327

iTrader: (13)

I think you got your info flipped there.

The 187 (last 3 digits of casting number) heads are the crappy junk swirl port heads
The L69 305 HO engine used the 416 heads which are much better heads.

The 416 heads (L69 305 HO) flows 195cfm intake

The 187 heads flows much less.. 165 cfm intake

The 416 heads responds very well to porting and a 1.94" intake valve upgrade.. You can get 220-230 cfm out of the 416 heads if you try hard enough, but IMHO in todays world it's just not worth the money or time to fool with porting, bigger valves, etc. You end up with $500, 800 in a set of 305 heads that flows 230 cfm..

When you can buy used vortec heads for $100-300 that flows the same thing, or aftermarket alum heads for $1,000 that flows 250-260 cfm.

In your case, I would use the stock L69 416 heads... If you feel up to it, maybe try to do some light home porting on the heads.

Put new valve seals on.

replace the valve springs.. I would use Elgin 943XK at $24 a set or howards 98214 at $30 a set

The comp XE262 cam looks about right. It's the biggest you would want to go with.

Use fel pro 1094 head gaskets

Stock SBC rocker arm stud size is 3/8"
5/16" is the push rod dia.

At this point with yours unless you find an awesome deal on used roller rockers, you will just be throwing money away. Not enough gain for the price. Roller tips for $110-180 will gain you maybe 5-8 HP. Full roller rockers for $240-290 will gain you 12-15 hp or so.

If you do buy rockers, do your research. Cheap ones will fail and when they fail they can trash your whole engine.
For roller tips I like Elgin, comp magnums.
For full rollers I like Howards, scorpion, harland sharp, crane gold race, comp ultra gold, comp ultra pro magnums.

Stay far far away from procomp, proform, etc brand rockers.

1.5 ratio rockers would do the best here. The XE262 is a modern profile cam with pretty fast ramps, no reason to try to toy around with 1.6's to fix something that don't need fixing.

I do use 1.6 rockers a good bit, but only when the cam has a slower ramp lobe profile, or heads flows much better at higher lift and i'm trying to get cam lift up more with out changing duration much.

I think the dual 2.5" pipes are over kill and may cost you some low rpm torque with your build. I feel you just don't have enough engine to need true duals or pipes that big. I have ran true duals on third gens for 15+ years and boy let me tell you, it's a pain unless you really need them.

Go with a mandrel bent Y pipe and single 2.75" pipe, maybe 3"

Oh you have not mentioned induction side of engine.. Your stock intake needs to go. Edelbrock performer or performer rpm would be better.

dodgeitclevelan

Thanks for your fast reply. I will definitely get the intake now. I will hate to do it but I will put the chappy 187 heads on until I get some vortecs then. I have always loved the sound of true duals that's really the only reason why I wanted them lol. I just want to get a third car for my wife and I at least for a month until I can some new heads. Not that it matters but how much power will lose when I put the 187 heads on? And when I do get the new vortec heads will that put me at my goal of 300 ft. pounds of torque? Thanks again for your replay

Night rider327

iTrader: (13)

Your 416's will get you to your goal.

The 187's will kill off around 30 HP or so vs the 416's.

The 062/906 vortec 350 heads will gain you around 35 HP over the 416's, and 60-70 HP over the 187's.

If you are thinking about vortecs, then do not buy an intake yet. You will have to have another style intake for the vortec heads as they only have 8 intake bolts plus taller intake ports.

12 years ago or so, Lunati built a 305 with 416 heads. It was a high compression engine. I think it was 10.25:1, 416 heads fitted with 1.94" intake valves, gasket matched, alittle bowl blending, old tech by today's standards lunati streetmaster 225@.050" cam with .477" lift, 108 LSA, edelbrock RPM intake, holley 600cfm double pumper, accel blueprint HEI, 1-5/8" tube headers.

It made 343 HP, and 356 ft lbs torque.

Dropping down to normal compression like 9.0 to 9.5:1 that same engine would be at somewhere around 325 HP/338 ft lbs.

The cams of today like the xe262 would make more power than that old lazy ramp streetmaster cam, so it would pick up atleast 10 more HP from the better cam.

2005Impalla

Don't swap the heads. I would run a single 3" exhaust, eliminate the cat and forget about the roller rockers as there not a good investment for the small HP gain. Spend your money on something better. When you go to vortecs you will have to get different rocker arms so it will be a waist of money. Its amazing how just a cam swap can change the personality of a car. The 262 cam is a great pick for what you plant to do. Maybe spend the money you would have spent on swapping the heads and rocker arms on something your going to use later in the future like a used set of vortecs, a carburetor or some suspension parts to help you lay down the extra power your planning on making. Old suspension bushings suck.

dodgeitclevelan

Thanks to both you guys. Yall helped me out a lot lol. Will post pics when done. I also got a nice dress up kit from GM High Performance.