Noob needs info on LT1 w/castiron heads

[windsma]

Hi ive been all over camaroz28.com with this one.

I need to replace my LT1 in my 93z28.
I finally found one close but it is from a 95 Caprice LT1 w/ castiron heads.

I can cram it into my z and be done.
or
I have a NIB comp cam model no. 07-502-8 / LT1 XR269HR-12
specs:218/224 dur. @.050 495/503 lift LSA 112
Ill do a valve job, 1.6RR's, and new valve springs? (any suggestions on the springs)

So the heads will be pulled , which ones should i reuse the Alum. or Cast.

I have gotten a response from my Z guys but they may be bias.

What do you B-body guys suggest as an engine combo, (i still have all my old 93 stuff in good condition) any thing different/better like injectors, opti, fpr, tb,etc...

Thanks everyone,
Matthew

[awizeking]

hey even thow they are the same motor in a way,they are mildly differnt,like the water jackets,an other smaller things that will not macth well together.goggle Brent's F-Body Links Page an scroll down to engin section an you'll find the differances.i had no idea either but between 93 an 96 thire are many differnt types in small areas.i might of read it wrong but this will help you in your quest.look at lt1 rebuilding under engins

[windsma]

the cams and opti's are diff. but Comp cams said the cam i got was for the 93-96 Lt1's ????????????? Even though the 95 opti requires a different dowel.
i couldnt find anything else. 2 knock sensors, Thanks for the Brent's F-body search ive never heard of it. Had alot of good info.


Which is the better OPTI, vented or non?

[96slow6]

the cams and opti's are diff. but Comp cams said the cam i got was for the 93-96 Lt1's ????????????? Even though the 95 opti requires a different dowel.
i couldnt find anything else. 2 knock sensors, Thanks for the Brent's F-body search ive never heard of it. Had alot of good info.


Which is the better OPTI, vented or non?
The 96-97 opti is the vented style. It is the better of the 2.

[69LT1Bird]

If you keep researching you will find that the iron heads out flow the F car heads from the factory. The Corvette aluminum heads used the dies from the iron Impala head. The only power loss is minimal from heat dispersion from aluminum and iron. Setup correctly, these engines run cool anyways. The blocks are indentical, the Corvette had 4 bolt mains but the F car and B/D cars have the 2 bolt setup. Crane makes a set of drop ins that will work for your cam selection. They are the beehive design. 63609 I think is the part number. They are mad for the iron head LT1 and the Vortec heads.

[windsma]

Thanks im not sure what u mean by this , (i googled the part no and nothing.)

"They are the beehive design. 63609 I think is the part number. They are mad for the iron head LT1 and the Vortec heads."

[69LT1Bird]

http://www.cranecams.com/index.php?show=browseParts&action=partSpec&partNumber=10309-1&lvl=2&prt=34

[awizeking]

if you look at the brent f body page i gave you it will show an tell you the diffs in the heads an what not so you may better understand.

[Chris 96 WS6]

If you keep researching you will find that the iron heads out flow the F car heads from the factory. The Corvette aluminum heads used the dies from the iron Impala head. The only power loss is minimal from heat dispersion from aluminum and iron. Setup correctly, these engines run cool anyways. The blocks are indentical, the Corvette had 4 bolt mains but the F car and B/D cars have the 2 bolt setup. Crane makes a set of drop ins that will work for your cam selection. They are the beehive design. 63609 I think is the part number. They are mad for the iron head LT1 and the Vortec heads.

They outflow the aluminum heads by MAYBE 3cfm intake...certainly not enough to be worth the extra 50 lbs or to overcome less spark advance you'll have to run to prevent detonation since the iron heads will hold more heat.

[69LT1Bird]

I have a 160 stat and my mechanical guage that goes into the rt head only shows 160, never has been above 170. I don't see the temp thing as an issue. I can't remember off the of my head but I am running a lot of timing in mine with no spark knock issue. Can't beat the iron heads for the price.

[CKJ]

The 96-97 opti is the vented style. It is the better of the 2.

The 95 is also a vented style, but the 95 year timing cover doesn't have the crank positioning sensor slot simply because the 95's don't have CPS's on the timing cover.

[AdioSS]

personally, I'd put the cam in with the aluminum heads. Your compression ratio increase will more than make up for the loss of airflow.

[ta8202]

I just went through this debate with my engine man the other month. I have a pair of the irons and aluminums. He told me to go with the irons he said they are a much better head. They flow atleast 10% better and are far more durable. Under monster horsepower the aluminum will also flex at different rates than the iron block. If you match Iron to Iron it is much tougher. I put a cam two sizes larger than yours in my Iron headed LT1. My engine man said I will be much happier with the Iron heads. He builds these all the time. You cannot pull quite the timing and get the quite the compression ratio with the Irons. With a good computer tune you surely can fix a lot of the timing problems. Compression is slightly lower it is rather minimal. If your running a cam the size you have or larger you need ALL the flow you can get.

[CKJ]

I just went through this debate with my engine man the other month. I have a pair of the irons and aluminums. He told me to go with the irons he said they are a much better head. They flow atleast 10% better and are far more durable. Under monster horsepower the aluminum will also flex at different rates than the iron block. If you match Iron to Iron it is much tougher. I put a cam two sizes larger than yours in my Iron headed LT1. My engine man said I will be much happier with the Iron heads. He builds these all the time. You cannot pull quite the timing and get the quite the compression ratio with the Irons. With a good computer tune you surely can fix a lot of the timing problems. Compression is slightly lower it is rather minimal. If your running a cam the size you have or larger you need ALL the flow you can get.

Dude...tell your engine builder to open up a Jegs or Summit book and look at the ratio of aluminum vs. Iron heads they sell. FYI, i don't remember seeing any aftermarket iron heads.

[Transamman25]

i would say time for a second opinion ... 3 cfm isnt 10% .... 50lbs is extra weight to get moving ... the corvette and f-bodies were built with one thing in mind ---speed .. i have a good idea and you'll know for sure which head to use ... call up Lloyd Elliott or Advanced Induction .. .either of those sources will be able to confirm which head is the right choice for your application

[mrcadillac]

The 96-97 opti is the vented style. It is the better of the 2.

Also, ALL B-body's got the vented opti. I've also seen venter opti's in 95 F-body.

[mrcadillac]

If you keep researching you will find that the iron heads out flow the F car heads from the factory. The Corvette aluminum heads used the dies from the iron Impala head. The only power loss is minimal from heat dispersion from aluminum and iron. Setup correctly, these engines run cool anyways. The blocks are indentical, the Corvette had 4 bolt mains but the F car and B/D cars have the 2 bolt setup. Crane makes a set of drop ins that will work for your cam selection. They are the beehive design. 63609 I think is the part number. They are mad for the iron head LT1 and the Vortec heads.

The early AL heads(pre 95?) flowed Less than the iron heads(there were 2 iron head castings, the 96's flowed 5cfm better on the exhaust, the 94/95 flowed 5cfm better on the intake.). How much, I don't know.

[mrcadillac]

Dude...tell your engine builder to open up a Jegs or Summit book and look at the ratio of aluminum vs. Iron heads they sell. FYI, i don't remember seeing any aftermarket iron heads.

I agree,not because of the jegs cataloge, you can push crappy part pretty easy. Ever checked out the advanced induction website? 96capricemgr has a set of early al heads on his caprice, ported to there 190cc port job, putting out over 500hp at the fly wheel... He's got alot of miles on those heads, and hasn't had any issues...