Author Topic: The hopefully better build thread than my last build thread, thread  (Read 88 times)

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Offline FCwidman

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So I have yet again bought another motor to build, only this time it is unfortunatly not a rotary engine. My buddy had a 4.8l ls sitting in his garage and needed it gone so i gave him a few doll hairs and now its torn apart in my garage at school.
 This time a have a better job and I'll have a job at school and will have much more free time to work on this project, so hopefully it doesn't end up like my s4 motor that I bought and get parted out. The engine has 230k on it and was pulled because it had a gnarly lifter tick, we thought that a cam lobe or lifter would be destroyed but everything in the engine looks pretty darn good for 230k,
This brings us to whats getting built on the motor,
                     -Cam(obviously) thinking ls6 or texas speed has a good deal going right now
                     - Lifters/pushrods
                     - Ls6 valve springs or the dual spring ones in the texas speed kit
                     - Ls1 intake or some aftermarket one that'll fit under the hood
                     - fbody oil pan and pulleys
                     - Leaving the bottom end stock, pistons and rods look perfect, I'll probaly get  new rings
                        though
Now I'm not sure if I'll be getting another fc shell or ruining my silver one yet, but if anyone comes across a cheaper clean roller (coupe or vert) thats not a million miles away let me know. Been looking at the grannys speed swap kit but was informed the ronin? mounts were better and gave more exhaust clearance. oh and also in the market for a used t56 if anyone knows of one.

I dont have too many pictures of the progress, cause we tore it down in about a day. but heres my table set up

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heres the only pic I have before the tear down
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Not too much progress will happen to the motor since it is in Big Rapids and I am back home in metro Detroit but that wont stop me from ordering a butt load of parts, so more pics of parts of as they come but for now if any one has some tips on what to get for the motor or for whatever chassis it goes into, let me know!

Online murz

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Can't wait to hear more on this, hoping you also find another shell for this too, everyone needs at least 2 RX7s.
1986 AS GXL Turbo swapped
1991 BB convertible
1993 VR R1

Offline FCwidman

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Hopefully I can get that t2 this weekend, also does anyone know anything about harness fitment? Will a truck harness work with ls1 intake and injectors or should I just get an ls1 harness. I'm pretty sure everything is the same except injector clips and tb.

Offline ITSWILL

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The truck harness will work fine. What trans are you going to run?

I have f body exhaust manifolds and ls1 heads. I also have ls6/ls3/ls9 valve springs and a bunch of other stuff too.
86 Base LS1 w/100 shot
88 TII 20B T70 turbo

Offline FCwidman

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T56 off an f body or whatever I can find, only thing I have right now for the swap is the actual engine. If I don't go with the Texas speed kit, I'll buy those springs off you, also how much better are the ls1 heads? I'm not looking to make a butt load of power just trying to keep the budget to a minimal. Manifold wise I havnt looked too much into it yet but saw a few things about a poor man's header? Definitely want some aftermarket mid or long tubes tho.
Any chance you have an f body oil pan or pulleys?
Also with the harness(which I don't have, nor pcm) I want to switch to cable tb, so any 98-03 harness should work?

Offline ITSWILL

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By the sounds of what you are talking about, headers will just increase engine bay temp and possibly leak. 

Juse make sure you get a harness for a gen 3 with rear cam sensor and valley mounted knock sensors. You can just remove the electric throttle body portion and anything to do with trans if you get one that was used on an auto. Manual is better though because you can operate the reverse lock out.

If you find you need a hand modifying the harness and getting it ready for the rx7 let me know.

And yes the ls1 heads are better. I also have injectors and possibly and an intake manifold.
86 Base LS1 w/100 shot
88 TII 20B T70 turbo

Offline FCwidman

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ehat other options are there for headers? I just figured I'd toss my rusty truck manifolds and get something tubular, was gonna wrap them anyway

I get that ls1 heads are better, but is it really worth spending money on if I'm only looking for like 300 ish wheel, but let me know how much you'd want for the heads and Intake stuff

Also just checked out the ronin swap kit, cheaper than granny's but didn't say anything about sway bar spacers in the complete kit, is it not needed with their kit?
Gonna hit up some junkyards and for sale pages for a pcm and harness soon, also might be picking up my donor car this weekend

Offline ITSWILL

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If you are only looking for 300-400hp the ls1 manifolds are fine. I'd sell mine for $100.

You mentioned putting a bigger cam in, that's why I suggested the heads. A bigger cam will call for better heads to get the most out of the cam. What casting number heads do you have? If you have 243 or 799 I would stick with those, but very few 4.8s had those. If you decide you want the ls1 heads I would sell them for 200 assembled as stock or 250 with new blue springs for a bigger cam.

I would sell the intake with injectors for 150.


86 Base LS1 w/100 shot
88 TII 20B T70 turbo

Offline FCwidman

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I don't recall what heads I have, I'll have my roommate snap me a pic. I've got my stock truck manifolds which look about the same, and my dad might still have his stock manifolds from his camaro.
Do you have the fuel rail too or will my truck rail work?
And I'm thinking I'm gonna order the Texas speed cam kit this weekend which comes with springs, what can do you think would work well if I do have the 243 heads? From scimming around ls forums I was thinking something around a 220/220 112lsa

Offline FCwidman

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Roomie went and looked at my heads for me, got the old 862's. So I might buy those heads off you, are they 243,799, or 823?

Online murz

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awfc3s has a good setup with a 4.8, he could probably send you a video of his car running and his specs over Facebook. It sounds pretty good. I'll try to get him to post something on here.
1986 AS GXL Turbo swapped
1991 BB convertible
1993 VR R1

Offline ITSWILL

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Truck manifolds don't fit.

My heads are 823s

What are your goals besides 300 hp? Is it going to be a daily driver or a race car? How do you want the idle, smooth or rough? Where dweeso you want your power range?

All those things impact the cam.

We put a 4.8 in Andrews car because the plan was to turbocharge it. He has a TSP 224 cam in his car and the idle is fairly rough, also he has a set of ported 5.3 heads on his engine. I believe he put down 265 to the rear tire.

I would still suggest the blue springs as long as you are going to stay below .590 lift. They are oem validated and are a very durable part.


86 Base LS1 w/100 shot
88 TII 20B T70 turbo

Online murz

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Hmm, he told me he put down 305 or 310 whp, maybe he was calculating crank hp.
1986 AS GXL Turbo swapped
1991 BB convertible
1993 VR R1

Offline ITSWILL

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You're right  it was 305, I think Kevin car made 365 that's where I got mixed up.
86 Base LS1 w/100 shot
88 TII 20B T70 turbo

Offline ITSWILL

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If I was building a 4.8 I would turbo it or make it rev to 8 grand.  Either is expensive. A stock ls1 can be had for about a grand. Unless you need the cast iron block or the shorter stroke it's a lot more cost effective to get 350 hp by just buyin and ls1.
86 Base LS1 w/100 shot
88 TII 20B T70 turbo