help me pick a head for my 402
help me pick a head for my 402 I have been getting frustrated with this whole deal. I called serveral places over the past week and i get a different response from everybody. I am probably going to go with the patriot heads for budget reasons, but every place i call tells me something different about what cc head to run, and what stage. I was told by some that i cant run a stage 3 patriot head, others say it is fine. One guy says go with a 62 or 64 cc head and the next tells me that will be way too much compression and to go with a 68 to a 72 cc head. These are all reputable places, I will not mention names. The shortblock i bought used and the guy i bought it from ran 62 cc heads with this cam and made awesome power, he said he ran it on pump gas and did not have any problems, I dont know what to think. When i run my specs on the compression ratio calculator i come up with 11.7 to 1 with a 62 cc head. I cant download a dcr calculator for some reason. so I am looking for some help. My setup is as follows, ls2 block to 402, 4.0 bore,4.0 stroke, je flattops with 2cc valve releifs, The pistons do not come out of the hole at all they are dead even with the deck, i plan on running a gm mls gasket so thickness is around .053 to .060 compressed, my cam is a comp 238/240 at .050 605/609 lift, 112 lsa with 2degrees of advance ground in and another 2 on the chain to give a total of 4 advance, valve timing at .006 intake open 34, exhaust open 79, close intake 74, close exhaust 31. If you need any more info just pm me and i will do what i can. I appriciate any help in advance.
With the pistons .007 out of the hole, a .053 thick head gasket, and 64 cc heads, I come up with a 11.82 SCR and a 8.86 DCR which I think would make excellent power. I would recommend you run AFR 225s.
I have been getting frustrated with this whole deal. I called serveral places over the past week and i get a different response from everybody. I am probably going to go with the patriot heads for budget reasons, but every place i call tells me something different about what cc head to run, and what stage. I was told by some that i cant run a stage 3 patriot head, others say it is fine. One guy says go with a 62 or 64 cc head and the next tells me that will be way too much compression and to go with a 68 to a 72 cc head. These are all reputable places, I will not mention names. The shortblock i bought used and the guy i bought it from ran 62 cc heads with this cam and made awesome power, he said he ran it on pump gas and did not have any problems, I dont know what to think. When i run my specs on the compression ratio calculator i come up with 11.7 to 1 with a 62 cc head. I cant download a dcr calculator for some reason. so I am looking for some help. My setup is as follows, ls2 block to 402, 4.0 bore,4.0 stroke, je flattops with 2cc valve releifs, The pistons do not come out of the hole at all they are dead even with the deck, i plan on running a gm mls gasket so thickness is around .053 to .060 compressed, my cam is a comp 238/240 at .050 605/609 lift, 112 lsa with 2degrees of advance ground in and another 2 on the chain to give a total of 4 advance, valve timing at .006 intake open 34, exhaust open 79, close intake 74, close exhaust 31. If you need any more info just pm me and i will do what i can. I appriciate any help in advance.
Patriot Performance - Part number 2035 - CNC Ported 243 LS6 / LS2 2.08"/1.60" 68cc Heads Assembled - $1295.00
You can call them toll free: 1-888-462-8276
A 64 cc head is what i came up with too, i just talked to larry at speed inc, since he is going to be doing the tuning, and with the info i gave him he said i could get a 64 cc head to work great, around 11.7 or so cr and run 93 octane pump gas, i will be taking a little more timing out for the nitrous anyway.
A 64 cc head is what i came up with too, i just talked to larry at speed inc, since he is going to be doing the tuning, and with the info i gave him he said i could get a 64 cc head to work great, around 11.7 or so cr and run 93 octane pump gas, i will be taking a little more timing out for the nitrous anyway.
That is alot of compression, but if that is what you want, that's cool.
Alot of people try to stay close to 11 to 1 max for pump gas, including me. That is probaly why people were telling you that was too much?
Good luck!
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Talked to jason at tsp today and he thought i should go with the 2.5 ls6 heads with the bigger valve option, very good guy to deal with. I think i will get them in a 64 cc chamber.
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Verdad Gallardo speedracer, is your calc on the dcr including the 4 total degrees of cam advance?? just wondering. I cant download a calculator on my pc (i dont have excel). I too would think that 11.7:1 would be too much compression, but both larry at speed inc, and jason at tsp ran the figures with what i had and said they did not see it being an issue running pump gas with the cam that i have. I do know that this cam is not going to have a lot of bleed off.
Yes that is with 4 degrees advance. When my motor was N/A I ran 11.8 SCR and about 8.8 DCR with no problems at all running pump gas. You can run alot my compression on these LS motor than you can on a traditional SBC on pump gas.
rpmauto - Where did you get the valve opening/closing specs from? Based on the specs you posted they are both XER lobes which have slightly different events listed in the lobe catalog.
FWIW - I'm going to run 11.8 static compression on my new setup and plan on using pump gas.
FWIW - I'm going to run 11.8 static compression on my new setup and plan on using pump gas.
my specs came from comp, i called them with the grind # on the cam (got it used so no cam card) and asked if they could fax me over all the specs. It does say that these specs are for a cam installed @110.0 int c/l if that makes a difference. Thank you guys for all your help