LS1TECH - Camaro and Firebird Forum Discussion

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-   Generation III External Engine (https://ls1tech.com/forums/generation-iii-external-engine-6/)
-   -   Which heads? (https://ls1tech.com/forums/generation-iii-external-engine/1912985-heads.html)

Grizzly76 01-07-2019 12:15 PM

Which heads?
 
Wondering which heads would be best for a turbo 4.8. have 2 options in mind since I can find both fairly easy and not that expensive. Would I be better off using stock 706 heads that come in the motors or would 241 heads be better for it? Hoping to reach about 6-700hp with it. The more details for each option the better for helping me decide. Thanks in advance

JoeNova 01-07-2019 01:20 PM

Whatever heads come on it.

03Sssnake 01-07-2019 01:34 PM

Keep the 706s

https://www.hotrod.com/articles/surp...der-head-test/

Grizzly76 01-07-2019 02:20 PM

What do I need to do with the 706 heads before I put them on? The ones I pulled off were ruined. One had a crack in it and there was coolant in a couple cylinders and the other one I ruined myself trying to remove the manifold the correct way and breaking 2 of the bolts off in the head. Things didn't go to well trying to extract them. I can get a set of 706 heads from the pull a part for cheap though so what needs done other than a thorough cleaning?

03Sssnake 01-07-2019 05:42 PM


Originally Posted by Grizzly76 (Post 20026844)
What do I need to do with the 706 heads before I put them on? The ones I pulled off were ruined. One had a crack in it and there was coolant in a couple cylinders and the other one I ruined myself trying to remove the manifold the correct way and breaking 2 of the bolts off in the head. Things didn't go to well trying to extract them. I can get a set of 706 heads from the pull a part for cheap though so what needs done other than a thorough cleaning?

I'd have a machine shop inspect them, pressure test them, lap the valves and clean them up. You could spend more porting them, but then I'd honestly start considering aftermarket heads.

wannafbody 01-07-2019 07:24 PM

I'd do 243 heads if you need to buy a set of heads.

Mavn 01-07-2019 11:10 PM


Originally Posted by wannafbody (Post 20026980)
I'd do 243 heads if you need to buy a set of heads.

Don't do this.. Lol I did this. terrible idea Slowest spooling turbo lag from no compression everrrr. 4.8's with a 243 head net an 8.8:1 compression ratio. Keep the 706's mill them 20. and run the SUM-8715 and let it eat!

Grizzly76 01-08-2019 01:57 AM

I don't wanna do any machining to anything if I don't have to. Just looking to refresh everything I can that's reusable and send it. It was a $200 dollar motor and my first build so I don't expect it to last a lifetime. Just gonna have fun with it and build something bigger in the mean time the correct way for big power... What are some other options I can do with them?

383z 01-08-2019 02:39 AM

Milling heads are CHEAP! Like $100 or a tad more. Do it!!

Grizzly76 01-08-2019 02:55 AM

I would if I was taking the build way more serious but I'm too cheap to do it for this one. Lol. Any ideas on head gaskets? Always read about the ls9 gaskets being top dog but would they be good for a 4.8?

wannafbody 01-08-2019 07:12 PM


Originally Posted by Mavn (Post 20027084)
Don't do this.. Lol I did this. terrible idea Slowest spooling turbo lag from no compression everrrr. 4.8's with a 243 head net an 8.8:1 compression ratio. Keep the 706's mill them 20. and run the SUM-8715 and let it eat!

I didn't realize that compression would drop that low.

Grizzly76 01-08-2019 11:30 PM

Should I get new lifters and push rods or would I be able to get away with using factory ones?

Grizzly76 01-09-2019 05:42 AM


Originally Posted by Mavn (Post 20027084)
Don't do this.. Lol I did this. terrible idea Slowest spooling turbo lag from no compression everrrr. 4.8's with a 243 head net an 8.8:1 compression ratio. Keep the 706's mill them 20. and run the SUM-8715 and let it eat!

Since it was mentioned, how is that ghost cam? Anyone use it?

03Sssnake 01-09-2019 02:23 PM


Originally Posted by Grizzly76 (Post 20027655)
Since it was mentioned, how is that ghost cam? Anyone use it?

check this out...

https://ls1tech.com/forums/generatio...ady-track.html


Grizzly76 01-09-2019 02:50 PM

I was thinking the SUM-8716 for mine. Not sure on a turbo to go with it. Any budget friendly ideas on a combo?

01CamaroSSTx 01-10-2019 07:19 PM

Is there a reason other than a slight compression bump that you wouldn't run the small bore 862 heads?

Grizzly76 01-10-2019 10:27 PM

Nothing other than possibly being slightly misinformed. That's why I came here to ask. I've seen both ways done but am unsure which way is the best way. Obviously using the stock ones was my cheapest bet which is great but, if the other way was a better way to go I wouldn't mind to spend a little extra you know

01CamaroSSTx 01-11-2019 07:47 AM


Originally Posted by Grizzly76 (Post 20028828)
Nothing other than possibly being slightly misinformed. That's why I came here to ask. I've seen both ways done but am unsure which way is the best way. Obviously using the stock ones was my cheapest bet which is great but, if the other way was a better way to go I wouldn't mind to spend a little extra you know

If you wanted to invest in them you could have them ported and machined for the larger 2.00" intake valves and gain some more. I'm just guessing here but for a boosted application I suppose people opt for the larger cc heads to keep the compression down in order to throw more boost at it. Perhaps the smaller bore heads will allow the turbo to spool faster.

Grizzly76 01-11-2019 07:55 AM

I'm not sure how it all works. I have read that lower compression is better for more boost but you don't wanna drop it a hateful amount. It's just my first build so I don't wanna throw 8g in parts at it and destroy it the first time I start it. Lol. I just wanna set it up for 600-700 hp range and throw it in something to have fun with for street/strip purpose. I will do a better build on another one if I like the results with this one.

03Sssnake 01-11-2019 08:10 AM


Originally Posted by Grizzly76 (Post 20028968)
I'm not sure how it all works. I have read that lower compression is better for more boost but you don't wanna drop it a hateful amount. It's just my first build so I don't wanna throw 8g in parts at it and destroy it the first time I start it. Lol. I just wanna set it up for 600-700 hp range and throw it in something to have fun with for street/strip purpose. I will do a better build on another one if I like the results with this one.

The compression was fairly low for the 4.8, think around 9.47:1 for the earlier ones like the LR4.


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