MS4, PRC 5.3 2.5's or AFR 205's??
01-21-2008, 06:14 AM
#1
MS4, PRC 5.3 2.5's or AFR 205's?? I just pulled my motor last weekend to do H/C and new rod bolts (it's a '98 and I figure better safe than sorry). I purchased an MS4 a little while back and was just planning on going with the PRC 5.3 Stg 2.5's from TSP milled to 59cc. Well I recently found a pair of used AFR 205's milled to 62cc for sale and was wondering if this would be a better choice for me? Will this make more power, if so how much would you guys guess? I'm trying to see if it's worth it.
Also, would flycutting still be necessary and what size pushrods would I need to use?
I will be spraying in the future, how do the AFR's respond to nitrous compared to the higher compression of the PRC's?
Thanks!!
Also, would flycutting still be necessary and what size pushrods would I need to use?
I will be spraying in the future, how do the AFR's respond to nitrous compared to the higher compression of the PRC's?
Thanks!!
01-21-2008, 09:00 AM
#2
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With the PRC's milled to 59cc...yes flycutting would be necessary. I have the same heads and cut .080 out of the intake side when I had the Torquer V3. An issue with three of the lobes forced me to another cam.
Have you decided on what type and thickness head gasket you are going to go with? That will play into your PTVC as well. Your only option is to measure..... with whatever head you go with. You can clay the pistons or use a dial indicator. I chose to clay mine. If you do use clay...make sure you use modeling clay and NOT playdough. There are lots of posts that members have made that describe how to do it if you are unsure.
As for the pushrods... measure for correct length. Spend the 20 or so dollars on a pushrod length checker. Its very easy to use and you'll be dead on. Again...lots of posts on how to use it. Remember to factor in your desired lifter pre-load after you get your measurement and add that to your number. That will be your PR length.
The flycutting portion will be easy since the engine will be out of the car. I cut mine with the engine in the car and it was a PITA. I used an angle drill and still had to cut my guide rod about 4 inches to get the drill to clear on the passenger side. I would recommend the Lindy Tool cutters over the Isky. There is also a member on the board that has started to make his own cutters that are in a trial basis. If you want the contact info for Lindy Tool I will pm it to you since they are not a sponsor. I believe the board members screen name is Quick346.
Good luck on your build and keep us posted.
R/
Frat
Have you decided on what type and thickness head gasket you are going to go with? That will play into your PTVC as well. Your only option is to measure..... with whatever head you go with. You can clay the pistons or use a dial indicator. I chose to clay mine. If you do use clay...make sure you use modeling clay and NOT playdough. There are lots of posts that members have made that describe how to do it if you are unsure.
As for the pushrods... measure for correct length. Spend the 20 or so dollars on a pushrod length checker. Its very easy to use and you'll be dead on. Again...lots of posts on how to use it. Remember to factor in your desired lifter pre-load after you get your measurement and add that to your number. That will be your PR length.
The flycutting portion will be easy since the engine will be out of the car. I cut mine with the engine in the car and it was a PITA. I used an angle drill and still had to cut my guide rod about 4 inches to get the drill to clear on the passenger side. I would recommend the Lindy Tool cutters over the Isky. There is also a member on the board that has started to make his own cutters that are in a trial basis. If you want the contact info for Lindy Tool I will pm it to you since they are not a sponsor. I believe the board members screen name is Quick346.
Good luck on your build and keep us posted.
R/
Frat
Last edited by Fratsit; 01-21-2008 at 09:08 AM. Reason: More info.
01-21-2008, 09:06 AM
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Id say the 205's are going to make more power for sure. The 5.3's seem to flow well but they have a larger cross section width which slows the air speed down considerably. Id say if you can afford the 205's go for it, i think you'll be happier in the end!
01-21-2008, 09:16 AM
#4
AFR = no brainer. Just mill if compressions an issue. Wish I could find a set used d@mnit!! Go for it!
Be careful about the rod bolts. Search the threads on here about guys who had probs after changing. SOMETIMES this requires the rods to be resized. A couple guys had rod knock after switching. I was gonna do it too when I do my H/C swap but decided to just go with a setup I don't have to spin my 98 over 6400-6500. Oh, I remember this too. Katech bolts are ok to swap straight in but they are $$$ and hard to find. Good luck!!!
Be careful about the rod bolts. Search the threads on here about guys who had probs after changing. SOMETIMES this requires the rods to be resized. A couple guys had rod knock after switching. I was gonna do it too when I do my H/C swap but decided to just go with a setup I don't have to spin my 98 over 6400-6500. Oh, I remember this too. Katech bolts are ok to swap straight in but they are $$$ and hard to find. Good luck!!!
Last edited by SOMbitch; 01-21-2008 at 09:26 AM.
