Hey guys. I have sought your help in building up my 68 Firebird and your knowledge has been great thus far. I recently bought a low milege 1967 400ci engine with an Ohio Crankshafts 455ci 4030 crank, 6X Heads and forged AutoTech pistons. The motor cam with a Schneider 290H cam and a Hurricane intake. The motor was originally setup for a high RPM application and I want to make it more street friendly. It's going in my 68 Firebird with a Tremec 3550 trans (low 3.27 first gear) and 3.42 reared gears. I already have a Performer RPM intake and am looking for camshaft recommendations. The car it a street car that will never see slicks, but it is only driven on once days and driven hard. I'd like a real choppy muscle car idle as well, and already have a vacuum canister for added power brake support.Thanks
schneider0602 (300H) HFT 290 310 230 248 0.510 0.510 0.561 0.561 110buy a lunati 60904 Product DescriptionHydraulic Flat Tappet Cam. Hot street or bracket cam for 350 *** engines or heavier 400-455 *** vehicles. Will need 9.5+ compression, 2800-3000 RPM stall converter and 3.42-3.73 gears. Likes up to 200 HP nitrous. Very rough idle quality. * Advertised Duration (Int/Exh): 276/284 * Duration @ .050 (Int/Exh): 233/241 * Gross Valve Lift (Int/Exh): .504/.527 * LSA/ICL: 110/106 * Valve Lash (Int/Exh): Hyd/HydA 60903 cam will have a wimpy idle. Your crank is Chinese but it's ok.COMPRESSION - I would run around 9.7 staticHEAD FLOW - Also if your heads are heavily ported they still suck you will gain around 10 zillion hp by bolting on some ported aluminum heads. ported x specs.0.500 251 0.500 2250.600 255 0.600 231if you have D port headers already, i would buy the 85 cc KRE's in the link below then pay $290.00 each to get them cnc ported to 290 cfm and if you have extra cash pay to get the chambers cnc'd.http://www.krepower.com/Pontiac%20Aluminum%20D-port%20Cylinder%20Heads.htmthe other option is ported eddy heads from butler.BPI-EDL-87CC-D PORT - 87cc Ported Heads with Ferrea Valves, 10degree Retainers & Locks, ARP 7/16 Studs, Hyd, Hyd Roller or Solid Springs 290-300 CFM @28" (220 Exhaust) $2595.00http://www.butlerperformance.com/products/cylinder_heads/edelbrock_aluminumD_Port.htmROD BOLTS - Make sure they are ARP or similar.GEAR RATIO - It would be a lot happier with 3.55's even with the 3.27 first.That trans is going to grenade anyway so sell it on ebay or craigslist before it does and if you do a lot of long distance fwy driving buy the .64 od, otherwise buy the .82 od. If 3rd on the 600 was 1.30 it would be ideal.Tremec TKO-500 5 Speed p/n 4616 1 - 3.27 2 - 1.98 3 - 1.34 4 - 1.00 5 - 0.68 Tremec TKO-600 (Street) 5 Speed p/n 5009 1 - 2.87 2 - 1.89 3 - 1.28 4 - 1.00 5 - 0.64 Tremec TKO-600 (Road Race) 5 Speed p/n 4618 1 - 2.87 2 - 1.89 3 - 1.28 4 - 1.00 5 - 0.82
Hi Paul,+1 on a Lunati cam, ***Running the numbers- Not knowing if you block has been bored and/or deck height trimmed/heads milled, Wallace racing calculators give you CR @ about 8.5:1. I assumed 101 chamber volume (the 6x-4 used on 350 CID motors, has 93cc)SHy is right, for the Lunati 904 cam, you would need static CR @ 9.5-9.7.Has your block been bored/deck height trimmed? have your heads been milled? are your heads 4's, 6's or 8's? they all have the 1.66" exhaust valves which are not the best for higher RPM suitability.I'd also check for hood clearence on the performer RPM as it's pretty tall.
Thanks for the input guys, I should have mentioned it in the first post but I'm doing this build on a budget and while I'd love a set of aluminum heads and a new TKO600 Tranny, I really don't "need" a 600ftlb torque for a weekend street car. Without slicks I think the difference would be a ton more smoke anyways. I had a stock 350 in the car to begin with, so this new combo will be a huge step up anyway. Maybe a few years down the road I'll throw on a set of heads.What I'm looking for is a choppy cam that will work well with these heads and these heads for a fun weekend street car. I will take a look at them to see exactly which chamber heads they are. Also the block was bored .030 over.Thanks
hello;unfortunately you can't have your cake and eat it too. choppy means big cam which requires big head flow.there's not a chance in heck that i would stuff a 60904 cam in a set of unported 6x heads so you also need to determine how much they are ported if they are.it's looking like the 60903 with the semi wimpy idle may be your most realistic option but we'll see.
+1 For a "choppy" cam, it'll be ground with close ICL and lots of over lap which does not work well with your low compression heads. The lower the CR, the less over lap you want to save as much compression as possible. The "bigger" the cam the lower your dynamic compression comes out.. as a general rule of thumb..... but there's a LOT of things to consider in cam selection.
shyrgfuh3 The Schnieder cam that is in the motor now is their 290HIntake Duration (gross): 280Exhaust Duration (gross): 300Intake Duration (.050”): 220Exhaust Duration (.050”): 232Intake Valve Lift*: .485"Exhaust Valve Lift*: .510"Lobe Separation: 110Intake Valve Lash: .000"Exhaust Valve Lash: .000"Would this cam work well with these heads and a RPM intake? It would be great to not have to swap cams, especially if the gains would be minimal.
I should have mentioned this from the beginning, but the motor is already together and has been dyno'd using a Hurricane Intake and the 290H Schnieder cam. It made the following power:RPM TQ HP2500 457 2183000 461 2633500 478 3184000 470 3584500 451 3865000 414 394Max TQ @ 3500 was 478Max HP @5200 was 397I just bought the motor from the guy who had it built, but he was planning the build for high RPM's and went with the Hurricane intake. The confusion thing for me is that this cam seems fairly tame with 220/232 duration at .050, but Schneider's website states that the RPM range is 2800-6400. Do you guys think this cam would work with the heads and RPM intake? I also thought about retarding this cam a little to drop the RPM band as well. I'm happy with the current power numbers, I just don't want to have to keep the RPM's up to keep the car from lugging in 5th gear.
On the Wallace Calculator I get a CR of 9.67:1 since the 400 blocks using a 455 crank, and is .030 over. Am I correct?
The heads are 6x-8 BTW
hello;You already know the cam will "work" with your heads because it has a dyno sheet which means that the engine actually runs so i don't understand your question.i suggest you read my previous posts.
hello;You already know the cam will "work" with your heads because it has a dyno sheet which means that the engine actually runs so i don't understand your question.i suggest you read my previous posts.those dyno numbers are weak.retarding the cam raises the power band.
Paul,when i ran the numbers, I used the following;400+304.21" stroke (455)101 CC's head volume(6x-8).041" gasket thickness w/4.205" diameter.025" deck height.comes up to about 8.5:1 CR
My71: According to the build sheet the deck was zero'd so when I run the numbers it comes up to 9.6Shy: Sure, I know that it "works" and that it runs. The question I'm asking is, should I swap cams before I put it in my car to achieve good street manners, or will this cam and the RPM intake be fine?