Which heads will work and fit to lower my compression on this setup??
Which heads will work and fit to lower my compression on this setup?? Hi Guys,
Long time member, read alot but don't post much. Hope this is in the correct forum category.
I have a tech question that I need to know which heads will work.
Here's the situation I have-- I have an opportunity to buy a LQ9 fresh rebuilt shortblock and unassembled LongBlock TSP 408 with the following specs--TSP Giant V2 Cam 248/254, 615"/622" 112LSA, PRC Stage 3 LS6-2.08/1.60-64cc heads, Diamond 4.010Bore, 4.000Stroke, Eagle LS1 6.125 H Beam Forged Rods,Eagle LS1 4.0 Stroker Crank.
I will be running a stock ECM box, Fast 92 intake, Fast 92 TB, 42 lb injectors and a T56. The setup comes with a tune for the 248/254 cam. This dynoed 490rwhp. I may later run a 125 N2O kit on there for a little fun??
First let me say that I am new to the LS motors and all of my previous education has been Gen1 and LT1 so I do not know exactly how the LS eats up duration and how the LS with bigger cubes tones down duration compared to the Gen 1 SBC's.
I have 2 issues that relate to my final listed below questions, first, I think this cam is way to big for what I want. I am building a street car 2nd gen Trans AM with an LS?/T56 setup but want good street ability, good but choppy idle and it will be a weekend fun car but do not want full race setup. So I assume I want low torque for the street. I am thinking about maybe the TSP 233/239 on a 112 or 113 or the TSP MS3 or MS4(magic stick4). I assume I will use no more than a .060 head gasket??
The second issue I have is that the compression I calculate with these -2cc pistons and the 64cc LS6 style heads will be to high for pump gas.?? Maybe around 11.6 or 11.8??
So with these details listed, here are my questions--
-Can I open up the chambers of the existing PRC 64cc heads to a 71/72 to bring the compression down to a 10.8/10.9 for 93 pump gas?
-Will that affect any performance besides that lost with less compression?
-If you guys say that the existing cam is fine and streetable, (please explain, as on my Gen1 SBC standards that is a big cam), is there any way to bring down that compression with the current setup.
-If I put a PRC LQ9 set of stage 2.5 - 72cc heads on there will they clear the -2cc pistons and will they sufficently lower my compression ratio below 10.8/9?
-What do you guys think is a safe compression ration for 91/93 pump gas on my setup?
-Should I keep these LS6 type Stage 3 heads, go with a L92 head(if so which one) or some other head?
-Will the springs for the existing 248/254 cam be to much for the other cams I listed?
-What do you think the HP output is for my cams of choice? Is there a better streetable cam head setup for me?
And last, I'm in my 40's and don't want a loud, loud car like I did when I was younger. Is there a muffler/exhaust setup you reccommend that will quiet down and mask the existing cam or any of the listed cams a bit.
Sorry this is a bit long. Thanks so much for any input you can provide for my potential new setup!
Long time member, read alot but don't post much. Hope this is in the correct forum category.
I have a tech question that I need to know which heads will work.
Here's the situation I have-- I have an opportunity to buy a LQ9 fresh rebuilt shortblock and unassembled LongBlock TSP 408 with the following specs--TSP Giant V2 Cam 248/254, 615"/622" 112LSA, PRC Stage 3 LS6-2.08/1.60-64cc heads, Diamond 4.010Bore, 4.000Stroke, Eagle LS1 6.125 H Beam Forged Rods,Eagle LS1 4.0 Stroker Crank.
I will be running a stock ECM box, Fast 92 intake, Fast 92 TB, 42 lb injectors and a T56. The setup comes with a tune for the 248/254 cam. This dynoed 490rwhp. I may later run a 125 N2O kit on there for a little fun??
First let me say that I am new to the LS motors and all of my previous education has been Gen1 and LT1 so I do not know exactly how the LS eats up duration and how the LS with bigger cubes tones down duration compared to the Gen 1 SBC's.
I have 2 issues that relate to my final listed below questions, first, I think this cam is way to big for what I want. I am building a street car 2nd gen Trans AM with an LS?/T56 setup but want good street ability, good but choppy idle and it will be a weekend fun car but do not want full race setup. So I assume I want low torque for the street. I am thinking about maybe the TSP 233/239 on a 112 or 113 or the TSP MS3 or MS4(magic stick4). I assume I will use no more than a .060 head gasket??
The second issue I have is that the compression I calculate with these -2cc pistons and the 64cc LS6 style heads will be to high for pump gas.?? Maybe around 11.6 or 11.8??
So with these details listed, here are my questions--
-Can I open up the chambers of the existing PRC 64cc heads to a 71/72 to bring the compression down to a 10.8/10.9 for 93 pump gas?
-Will that affect any performance besides that lost with less compression?
-If you guys say that the existing cam is fine and streetable, (please explain, as on my Gen1 SBC standards that is a big cam), is there any way to bring down that compression with the current setup.
-If I put a PRC LQ9 set of stage 2.5 - 72cc heads on there will they clear the -2cc pistons and will they sufficently lower my compression ratio below 10.8/9?
-What do you guys think is a safe compression ration for 91/93 pump gas on my setup?
-Should I keep these LS6 type Stage 3 heads, go with a L92 head(if so which one) or some other head?
-Will the springs for the existing 248/254 cam be to much for the other cams I listed?
-What do you think the HP output is for my cams of choice? Is there a better streetable cam head setup for me?
And last, I'm in my 40's and don't want a loud, loud car like I did when I was younger. Is there a muffler/exhaust setup you reccommend that will quiet down and mask the existing cam or any of the listed cams a bit.
Sorry this is a bit long. Thanks so much for any input you can provide for my potential new setup!
high 11's compression is plenty fine on 93 pump, that cam is a bit large for a 403ci but would not be a problem if you have a good tuner and would eat the nitrous up.
with -2 cc pistons, 64cc heads, 4.01 bore, 4 stroke and even a ls9 head gasket (4.1 bore, .055 compressed) im getting 12.2:1 compression... would be fine with 93 pump doubt it would be recommended for 91, but it all depends on the cam!
I would run it if you want a stout n/a setup. as far as mufflers/exhaust... im still trying to figure out how to quiet down my car without restricting it too much and without running cutouts..
with -2 cc pistons, 64cc heads, 4.01 bore, 4 stroke and even a ls9 head gasket (4.1 bore, .055 compressed) im getting 12.2:1 compression... would be fine with 93 pump doubt it would be recommended for 91, but it all depends on the cam!
I would run it if you want a stout n/a setup. as far as mufflers/exhaust... im still trying to figure out how to quiet down my car without restricting it too much and without running cutouts..
