Can anyone tell me how these two cams compare? The poston cam is generally not thought too highly of, but I hear good things about the SP4. They have almost the same specs. Poston- 252, 272 @.050"- around .540" lift on a 110 LSA, SP4- 253, 270 @.050"- around the same lift, 110 LSA. Is there a major difference in lobe geometry on these two, or what is it that makes the SP4 good, and the GS110 not very good? Or, is it the way they are advertised? Poston seems to make their cam sound a lot milder than what I've heard it actually is. Maybe expectations or the combination are off because of this? I would think either one would require a 3500-4000 stall converter, 3.73-4.11's, and ported heads to work well. Any thoughts on either of these? ________ Wendie 99
Poston's GS110 Jadebird Don't know about the comparisionon the SP4, but I do have some experience with the GS110. It was to much shaft for my car which is a blue printed 455 w\stage 1 heads ported and milled, and a B4B intake. I had all the other components they suggested to make this stick work. If you haven't got high flow heads and a lot of compression I wouldn't use the GS 110. My car has 10:5 compression and the low end torque was way off with the GS 110 and I didn't want to spin the crank RPMs where this thing wanted to fly. Off the line I had a huge flat spot which killed my 60" times and kept them in the 1.80 range even with a 4:11 rearend and a 4000 stall converter. My car weighed in at 3900lb and my best was 12:17 et @ 113 MPH. The GS 110 runs best @ 6000 RPMS or higher and you better have a lower gear than a 4:11 to your car moving. When I went to the GS 112 the flat spot went away, 60' times are 1.65, 11:90 et @ 113.5 mph. Weekender
Thanks for the information. Ironically I was trying to decide between a GS112 cam and a torque tech SP4 for a motor that will be similar to yours. It looks like you have made that decision for me! The combination I have in mind is: 464 with home ported iron heads, 10.5:1 compression, headers, B4B or maybe an SP1, 950 holley, 4.11's, 400 tranny, 3500 ATI treemaster converter. By the way, what was done to your block, as far as lower end work? I was wondering if I needed to use main studs or if I could get away with ARP bolts. I plan to bracket race it quite a bit and drive it on the street also. ________ Synthetic weed
I don't have any experience with the 110,but weve done several steet/strip motors with the 112 and I highly recommend it,one was running 11.6's with 10.8 to 1 compression and 4.10 gears gary
I don't have any experience with the 110,but weve done several steet/strip motors with the 112 and I highly recommend it,one was running 11.6's with 10.8 to 1 compression and 4.10 gears gary
Thanks, Gary. That's about what I am aiming for with my car- mid 11's. What kind of numbers were the heads flowing on that motor? What are your thoughts on block and rotating assembly for a motor like this? I was planning on just oiling mods, stock rods with ARP bolts, Wiesco 22cc dished pistons 0 decked, and probably main studs- no girdle. ________ Best buy gift cards
Its not the best street cam but I run the Poston 105a in my car with just under 10 to 1 compression and it runs real good. I was going to go to a SP4 cam with better heads this year, but I have had trouble with a sick kitty cat so vet bills have put a hold on my car for now.
With a .030 bore, 0 deck, 22 cc piston, .040" gasket and 65 cc combustion chamber your compression will be right at 10.8+/-. The heads we had flowed in the 260's on intake and upper 180's on exhaust.Have a good balance done on the motor,have it align honed,file fit the rings,main studs are good insurance,along with the oil mods make sure your oil pump is capable of providing the pressure and volume needed for a healthy motor.The converter is very important here too,I'd use a 3500-3800 made by Carl Byrd,these are the best,well made,good flash and lock up on top end,I could hook you up if you want to go that route. gary
SP4 cam. Hi Guy's, I am using the sp4 cam in my 70 stage 1. It has 10.5 to 1 compression and ported iron heads with 1.65 roller rockers and a wildcat intake with a barry grant 1000 cfm carb. TH-400 tran's and 390 gear ratio and run's on pump gas, Best 1/4 mile time when the air is good is 11.07 at 119 mph, 60 ft 1.55, hot summer day's is 11.50's to 11.70's, Car will go faster but a couple of broken 8.5 axles makes me take it easy on the launch. All in all it's a good camshaft and idles well and sound's wicked. Billy.
I talked to a guy years ago who ran the sp4 and wrote his combo down. It ran 1.55 60ft times with iron heads (flowed 275), 950hp, Mallory 140 pump, sp1, 3.73's, ati 3500 treemaster but with 11.5 comp.. Car weighed 3500 lbs., Ran 10.90's/121-123mph. Ray
Great info, thanks everyone. Gary, I would take you up on the converter, but I already have a brand new ATI ready to go. Next time I will wait until everything is finalized before making that decision- live and learn I guess. Thanks for the info on the shortblock. I was calculating the CR using a 68cc head with a .038" overbore, so it looks like our numbers are in agreement. Any chance of using pump premium in such a motor, with a little race gas mixed in at the track? I am getting the impression that the 112 would be the best choice for me. It more closely matches the spec my converter was built to. Also, it's probably better suited for the heads I will be using- not a maximum porting effort- I'm hoping to get 260's on the intake side. I would be really happy with a car that would run 11.5's on a good day, and is still somewhat streetable. For a bracket motor I like the idea of keeping the shift points to around 5800-6000. With a good short block the motor should last a long time that way. I get the impression the SP4 might need more stall and RPM to run those fast times. If I didn't have the converter already, I would likely go with the SP4. It will be a pinch for me financially just getting this thing running, so I have to work with what is available right now. ________ IPAD ACCESSORIES
Block issues Interesting you should ask, just had the block done. I did have the mains doweled, .003 clearance on the mains .0022 on the rods. I used Calico coated bearings which have worked the best for longevity because you not only have the .0005 of coating which is very slippery you have all the regular bearing material of the normal bearing with less heat generation. I also installed scavaging system and all the external oil feed mods to the rear of the right side oil galley (very important). I also installed an oil cooler (very important), which after having read all the debate on this issue, determined it is a must if you drive it on the street. I won't go into my temperature findings here, but I feel most of my lower end problems came from oil temperature and lack of oil form the center line of the engine back. If you use the GS 112 (which by the way is back ordered at Postons) I found a 3:70 gear works better as an all around gear. The 4:11 will lower those 60 ft times but at the cost of streetability and gas mileage, if that is a concern. Everything esle you have looks good together as a package. I currently have a TA 107C cam installed and wish I had my GS 112 back, but I couldn't get it due to back order. Weekender
Jadebird if you would like the GS112 or the Sp4 contact me as I have both these cams NITB. Let me know. Ray
Pump gas ?? No need for race gas! This combo with 10:1 to 10:5 compression will run 93 octane at 32 deg advance with the Vacuum hooked up with no detoation problems. This has been my experience. You might want to talk to Ray, on the GS 112 do to back order at Postons. If his camshafts are used, make sure he has the lifters that ran on that stick in the proper arrangement, if not buy a new camshaft. Weekender
