what will the compression ratio be?
Cam choice for 4.1................
Guys,
Bout to start ordering all the stuff to put this motor together. Here's the spec sheet. '84 4.1L "484" production block, .030 over with Venolia pistons, stock turbo crank and rods. The motor will be receiving a fully ported set of TTA heads with big valves. Fully ported and port matched intake. PT-70 with P-trim exhaust wheel and a Precision .63 housing. 3300-3400 stall 9/11 lockup from Bruce Toelle. The rear is a Moser 9" with 3.25 gears. I'm stumped as to what cam I should go with. This will be a 25% street car 75% track car driven on the weekends occasionally. I don't know if I should go roller or not, or which size. I have been told and it makes since also that a cam that is pretty big in a 3.8 won't be so radical in a 4.1 b/c of the 10-18% more cubic inches. Anyone out there with any good recommendations? Roller or not? Thanks.
------------------
Robert
'87 Turbo T
'89 Turbo Trans Am
www.Hi-psi.com
Bout to start ordering all the stuff to put this motor together. Here's the spec sheet. '84 4.1L "484" production block, .030 over with Venolia pistons, stock turbo crank and rods. The motor will be receiving a fully ported set of TTA heads with big valves. Fully ported and port matched intake. PT-70 with P-trim exhaust wheel and a Precision .63 housing. 3300-3400 stall 9/11 lockup from Bruce Toelle. The rear is a Moser 9" with 3.25 gears. I'm stumped as to what cam I should go with. This will be a 25% street car 75% track car driven on the weekends occasionally. I don't know if I should go roller or not, or which size. I have been told and it makes since also that a cam that is pretty big in a 3.8 won't be so radical in a 4.1 b/c of the 10-18% more cubic inches. Anyone out there with any good recommendations? Roller or not? Thanks.
------------------
Robert
'87 Turbo T
'89 Turbo Trans Am
www.Hi-psi.com
1 - 5 of 5 Posts
Probably 8.5-9.0:1 due to the short block having been assembled originally for a Turbo Regal, but I'm now going to use TTA heads and drop it in a TTA. I was thinking a 218/218 or 224/224. If I go roller, either a 214/210 or 210/210. Just not sure if I want to spend the money on the roller. For the price difference in the cams, that's half the money towards a Speed-Pro system.
------------------
Robert
'87 Turbo T
'89 Turbo Trans Am
www.Hi-psi.com
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Robert
'87 Turbo T
'89 Turbo Trans Am
www.Hi-psi.com
For the flat tappet, I would say the 218/218 or the Conley 221.
For a roller, I would say a 214/214 or the one you mention.
Go with a MaxEffort and save a ton of money on whatever name the Feldpro is going by these days (Speed?)
The slight increase in compression will allow you to go a bit bigger in cam as does the extra cubic inches.
Well ported heads are the real secret in these engines rather than a couple of degrees difference in the cams. Most of the so called cam tests and observations we see posted here are badly flawed and don't hold up to close scrutiny.
Remember the normal 4.1 block may be a bit weaker and probably should not be pushed to high rpm. I would think a girdle would help quite a bit.
For a roller, I would say a 214/214 or the one you mention.
Go with a MaxEffort and save a ton of money on whatever name the Feldpro is going by these days (Speed?)
The slight increase in compression will allow you to go a bit bigger in cam as does the extra cubic inches.
Well ported heads are the real secret in these engines rather than a couple of degrees difference in the cams. Most of the so called cam tests and observations we see posted here are badly flawed and don't hold up to close scrutiny.
Remember the normal 4.1 block may be a bit weaker and probably should not be pushed to high rpm. I would think a girdle would help quite a bit.
I'm leaning towards the 218/218 more and more. BTW, this block has had head bolt holes studded. I realize this motor doesn't need to see a lot of RPM's. I'm not a banzi runner, I'm usually fairly conservative on my state of tune. I thought about a girdle but I'm unsure of whether it will work or not in a TTA b/c of clearance issues. Anybody out there put a girdled motor in a TTA? Also,...anyone know if the TTA and Turbo Regal oil pans are the same?
------------------
Robert
'87 Turbo T
'89 Turbo Trans Am
www.Hi-psi.com
------------------
Robert
'87 Turbo T
'89 Turbo Trans Am
www.Hi-psi.com
1 - 5 of 5 Posts
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