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motor for daily use on 87 octane

  
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motor for daily use on 87 octane

 
catlikesbirds catlikesbirds
New User | Posts: 4 | Joined: 07/14
Posted: 07/19/14
10:31 AM

Hello Gentlemen,

I would like to build a 30 over 1966 389 cu. with 6x heads milled to 87 cc. prep by SD performance. I will use ram air cast exhaust manifolds and performer rpm intake. What hydraulic cam should I use?  Turbo 200 with 355 gears in a 77 trans am.

thanks  

gtojack1366 gtojack1366
Guru | Posts: 1265 | Joined: 11/09
Posted: 07/19/14
04:12 PM

Why do you want to use a 389 ?  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 483 | Joined: 11/13
Posted: 07/19/14
05:00 PM

hello;

yeah, why a 389?

a turbo 200 is not good for a high perf v8 unless it is the 200-4R model.

with flat top pistons with 2 valve reliefs and .030" over with 87 cc heads you get 8.58 static compression.

with this low compression the biggest cam i would run is around a lunati 60902.

http://www.lunatipower.com/Product.aspx?id=1775&gid=287

i would not run rhoades lifters.

the rpm intake is a bit too much for this set up.

the valves on those heads might hit a 389 piston die to the valve angle.  

idrivejunk idrivejunk
Addict | Posts: 5151 | Joined: 12/09
Posted: 07/19/14
05:03 PM

I thought the same. Reckon its always cheapest to fix what ya got. The build sounds like it could use a mild stock cam profile, or close to it. An RPM intake makes little sense to me with that compression that low and fuel that weak.  
idrivejunk

catlikesbirds catlikesbirds
New User | Posts: 4 | Joined: 07/14
Posted: 07/19/14
06:46 PM

Thanks you guys,

I have a choice of pontiac engines and felt that a 30 over 389 would provide  low enough compression to run whatever gas I can for a daily driver. I can run .000 deck and flat tops with reliefs for the 6x heads. Trans is Turbo 200 4r. What would be a better choice for a daily driven 2 ton car in 90 degree heat in central florida? I would want to get on it with the air conditioning blasting and the sun beating down on the shaker and have it move quickly without pinging or hesitation. Can I use a performer manifold and a Holley Street Demon with the goggle valve secondary? The heads flow 240 intake and 160 exhaust, heat cross over sealed, milled to 87 cc, ferrea ss valves ported by Rob at SD performance in B.C.I have 1.5 roller rockers and will be using 11 bolt water pump.

I appreciate your input and since I have a limited budget, I do not want to waste any on a combo I can't drive hard and loud on the piss water we call gas these days.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 483 | Joined: 11/13
Posted: 07/19/14
07:00 PM

lol, ok, yes our hreat gas, but guess what, E85 has a ron/mon octane equivalent of around 105. ine guy here is running 214:1 static compression on it. we saw thw video but have not gotten an update.


i do not know what you want to achieve exactly but i would do what i suggested with your compression.

i prefer a 400 eng. the engine size has litt;le to do witj compression because it can be altered easily.

a nice 500 cube with around 8.5:1 will cruise alomg nicely.

the std performer is good, a stock pontiac 400 iron intake is good.

i would run a holley or quick fuel annular booster vacuum secondary carb.

maybe my71 or rowslwy will comment.  

catlikesbirds catlikesbirds
New User | Posts: 4 | Joined: 07/14
Posted: 07/19/14
08:13 PM

Hello shyrgfuh3,

How did you calculate static compression? What would the static compression be for a 30 over 400 and 30 over 428 using the 87 cc heads?  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 483 | Joined: 11/13
Posted: 07/19/14
10:09 PM

http://www.wallaceracing.com/cr_test2.php

at the end of the day, you need to calculate dynamic compression as well as static.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 483 | Joined: 11/13
Posted: 07/19/14
10:14 PM

http://www.wallaceracing.com/cr_test2.php

at the end of the day, you need to calculate dynamic compression as well as static.

if you have more compression with a 455 you can simply buy thicker head gaskets from butler racing. not to worry, go for the gusto stroke a 455, lol.

a 400 should be quite happy. if you mill your heads to boost compressiion you can run the next size up cam. in general, the bigger the cam, the lower the compression. yes i know it sounds like it makes no sense.

the next bigger cam will be more mid and upper mid range with a slightly noticeable idle/lope.  

catlikesbirds catlikesbirds
New User | Posts: 4 | Joined: 07/14
Posted: 07/20/14
05:50 PM

Thank you for your replies,

I have a 67 400 cu. and a 1968 428 standard bores. I was afraid of using them because of the compression ratio and todays gas. I will contact the Butlers with my concerns as well as the pontiac forum as I move along.  

bigD bigD
User | Posts: 150 | Joined: 05/14
Posted: 07/20/14
08:05 PM

Icon Quotecatlikesbirds:
Thank you for your replies,

I have a 67 400 cu. and a 1968 428 standard bores. I was afraid of using them because of the compression ratio and todays gas. I will contact the Butlers with my concerns as well as the pontiac forum as I move along.


You can calculate a ballpark figure for your CR by plugging your specs into the CR calculator Shy mentioned. Here's the link to it.

http://www.wallaceracing.com/cr_test2.php

Just for practice, let's enter some of the numbers you gave.

(1) 400 + .030  with 87cc heads, SP L2262F30 forged flat tops with 6.7cc valve reliefs, .010 deck, .027 x 4.160 Cometic gaskets.  CR = 9.16

(2) With .036 x 4.160 gaskets, the CR = 9.00

(3) 428 + .030  with 87cc heads, Probe 14474-30 forged flat tops with 5.5cc reliefs, .010 deck, .051 x 4.20 gaskets.   CR = 9.34

(4) With .060 x 4.20 gaskets, the CR = 9.18

(5) With 14cc dish D.S.S. 6113X-150 pistons, .036 x 4.160 gaskets, .010 deck,  CR = 8.97

(6) With 10cc dish Icon IC892-30 pistons, .045 x 4.160 gaskets, .005 deck,  CR = 9.20

http://www.jegs.com/p/Cometic-Gaskets/Cometic-Pontiac-Cylinder-Head-Gaskets/1288713/10002/-1

Well you can see how you can play with gasket size, different pistons, and the other items and come up with exactly the CR you want. And for a few more $ you can buy custom pistons with different pin heights and reliefs or dish size, instead of cutting your deck and heads.   Smile