1 3/4 or 1 7/8 headers on a 427?
#11
it should still make decent power just at a different rpm range I've seen a 408 with a 222/232 and 11:1 dyno at 632hp not sure if I should go bigger with the 2 speed sniffer lol
#13
TECH Fanatic
Not trying to be rude at all here, but that setup is very miss matched, big cubes, big heads, small cam, low compression, not enough gear.
If it's low end torque you are looking for those heads are really hurting you, I went from prc 2.5 truck heads, 1 3/4 headers to tfs 245s, 1 7/8 headers and one step up on cam and my low end changed dramatically, the whole point of me changing to the larger parts was to lose low end to help with dig races on the street, move the power band up.
this was all on a 408.
But to answer your question, if you ever plan on stepping up the cam go 1 7/8, if you plan to keep the current setup then 1 3/4 will be fine.
If it's low end torque you are looking for those heads are really hurting you, I went from prc 2.5 truck heads, 1 3/4 headers to tfs 245s, 1 7/8 headers and one step up on cam and my low end changed dramatically, the whole point of me changing to the larger parts was to lose low end to help with dig races on the street, move the power band up.
this was all on a 408.
But to answer your question, if you ever plan on stepping up the cam go 1 7/8, if you plan to keep the current setup then 1 3/4 will be fine.
#14
As others said, 2" primaries would be preferable to either choice, but at least run the 1 7/8s.
#15
The ls3s had big ports on a smaller cubed motor and still pulled fine im going to be regearing to 4.56s eventually I'm not sure how much advance will be ground most likely 3-4 degrees, Either way I'm sure it's going to pull hard off the line and still be fun to mess with
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arthursc2 (08-10-2021)
#17
If you haven't gotten the cam yet, something like the TSP 228R on a 114 would probably be better for those cubes and still work with the sniffer. Then bump the compression closer to 11:1 (unless you really do plan that blower )
#18
Last edited by Cheyenne95; 08-10-2021 at 10:52 PM.
#19
how high could I go on the cam and still use a 2500 stall with those cubes and pass till? Lol I don't wanna put like a 3500 stall in and just not use my bottom end torque off the line if it helps my smog limits are 800 on both hydrocarbons and n0x and the test is run at idle and 2500rpm basically
Since your heads flow great on the exhaust, and couple that with large tube headers, it should run well on the single pattern cam, which then you can run a larger intake duration without worrying about too much overlap for emissions, which is why I mentioned the 228R.
Last edited by 68Formula; 08-11-2021 at 05:28 PM.
#20
The TSP228R reportedly has an IVC of 44 @ 0.050. This should easily work with the 427 and a 2500rpm stall. And with the 114LSA it results in 0 overlap @ 0.050. Not sure if you can go much more on the overlap even with a 427, and still pass the sniffer. Make sure your tuner knows your targets, because a lot is going to come down to them.
Since your heads flow great on the exhaust, and couple that with large tube headers, it should run well on the single pattern cam, which then you can run a larger intake duration without worrying about too much overlap for emissions, which is why I mentioned the 228R.
Since your heads flow great on the exhaust, and couple that with large tube headers, it should run well on the single pattern cam, which then you can run a larger intake duration without worrying about too much overlap for emissions, which is why I mentioned the 228R.