SS/GT Engine Choice

[Adger Smith]

Car will be a Gen 3 Camaro Badged as a IROC Z-28
Weight should put the car in GT/CA- GT/DA Depending on engine choice.
3 engine choices
Idea is to use parts & pieces I have laying around my shop
I Just want the best .50 - .80 under index runner.
1.
'69 427 425/445
4.311 bore 3.76 stroke
12.7 actual measured compression
401 Alum heads 2.19/1.845
780 Vac Holley carb
2
'70 402 375/405
4.185 bore 3.76 Stroke
12.58 actual measured compression
401 Alum Heads 2.19/1.88
780 Vac Holley carb
3.
'71 454 425/435
4.311 Bore 4 Stroke
10.96 actual measured compression
401 Alum Heads 2.19/1.88
780 Vac Holley Carb
4.
'71 454 425/424
4.311 bore 4 stroke
10.96 actual measured compression
Iron 188 or 990 heads 2.19/1.88
780 Vac Holley Carb
I like what combination Dwight Southerland suggested, but I want to use parts I have available. Yes, I'm a tight Arse!
If you don't want to make a public comment just DM/PM me
Thanks, all comments are appreciated
Adger Smith

[john ancona]

[QUOTE=Adger Smith;685052]Car will be a Gen 3 Camaro Badged as a IROC Z-28
Weight should put the car in GT/CA- GT/DA Depending on engine choice.
3 engine choices
Idea is to use parts & pieces I have laying around my shop
I Just want the best .50 - .80 under index runner.
1.
'69 427 425/445
4.311 bore 3.76 stroke
12.7 actual measured compression
401 Alum heads 2.19/1.845
780 Vac Holley carb
2
'70 402 375/405
4.185 bore 3.76 Stroke
12.58 actual measured compression
401 Alum Heads 2.19/1.88
780 Vac Holley carb
3.
'71 454 425/435
4.311 Bore 4 Stroke
10.96 actual measured compression
401 Alum Heads 2.19/1.88
780 Vac Holley Carb
4.
'71 454 425/424
4.311 bore 4 stroke
10.96 actual measured compression
Iron 188 or 990 heads 2.19/1.88
780 Vac Holley Carb
I like what combination Dwight Southerland suggested, but I want to use parts I have available. Yes, I'm a tight Arse!
If you don't want to make a public comment just DM/PM me
Thanks, all comments are appreciated
Adger Smith[/

1972 402

[Adger Smith]

John,
I like the oval port as we discussed, but don't have the pieces for it.
The only parts for the rectangle port combinations I need to buy is the pistons.
I have a nice worked 401 heads & intake & carb.
Thanks...

[Bob Sherwood]

71 425/435 Would weigh in GT/CA close to smaller motors in GT/DA with only a .10 difference in index --- less likely to get hit with HP ,not many running this motor, plus with 4 in stroke piston speed will flow a lot of air. Bob

[Dwight Southerland]

Knowing that when it comes to spending you are tighter than skin on a grape, the 454-425/435 is the best choice since you have the heads already.

What did I recommend before? I don't remember that conversation.

[Alan Roehrich]

I'd build the 402, at maximum bore size. With modern rings, good oil, etc, you'll get hundreds of passes on it.


If you have not purchased connecting rods and pistons, or ground the crank, I'd go with small block small journal and small block wrist pins, and a 1.0 MM/1.0MM/3.0MM ring package.


I think that I have a nice, conservative, stock core (billet) camshaft for it, that Billy and Tim did for me.



A certain wise and learned friend and I were discussing this on Thursday. For GT in particular.

[Adger Smith]

Alan,
This will be a shop clean out combination.
I have blocks, heads cams and a lot of parts needed just laying around the shop.
Yes, I will have to buy pistons, but not going the exotic expensive route.
Thanks for the info.

OH, Dwight Southerland... You ask me to keep silent on that combination.
My tight Arse is still gathering parts for it.
Yes, I have a set of the 401's and a set of iron 990's that Self worked.
So the 425/435 combo and the 425/424 combo are possible.
Might be safe with the 454 just in case one combo gets treated badly byAHFS.

Thanks
Adger

[Dwight Southerland]

Ah, yes! I remember now!

Depending on the flow characteristics comparison of your 401s and 990s, the 454-425/424 may be a better choice. In my recommendation, I was assuming you only had the 401s available and did not want to spend the money on another set of heads.

[Adger Smith]

Dwight,
The 990's were done by Kevin Self quite a few years ago.
The 401's were done by Tilburg
Guess I need to spend some time on my flow bench....
I was digging around the shop yesterday and found a 3.625 Bryant crank.
I might even consider a 390 cu in BBC for SS/AS
I would have fewer body modifications to the car. (former SS/DM) Going to have to do a lot to get to the Legal SS/GT body.
Donna says I have too many choices.
I'm in "Analysis Paralysis"
Thanks for the input.

[Alan Roehrich]

Originally Posted by Adger Smith

Dwight,
The 990's were done by Kevin Self quite a few years ago.
The 401's were done by Tilburg
Guess I need to spend some time on my flow bench....
I was digging around the shop yesterday and found a 3.625 Bryant crank.
I might even consider a 390 cu in BBC for SS/AS
I would have fewer body modifications to the car. (former SS/DM) Going to have to do a lot to get to the Legal SS/GT body.
Donna says I have too many choices.
I'm in "Analysis Paralysis"
Thanks for the input.

Sounds like you need to choose a combination, and hold a garage sale to raise money!


The modified route might be the most affordable, if the car requires rework that costs substantial money to get to legal status for GT. Considering how rare a heads up would be, it wouldn't have to be state of the art.


The 402 combination would probably be the most competitive, we've done a fair amount of studying and research. But it might be more expensive than the modified route, and more likely to face heads up races.