[KevinDush]

Hello. I am soon going to begin the rebuild of a 455 for my 76 Trans Am. It is an automatic (TH400) with 3.23 gears, which is driven daily (weather permitting), with regular strip action in the summer months. With the 400 in it now I ran a best of 14.6 @ 96mph. How does this combo sound?
1970 455 (out of a Bonnie Hearse, 360 hp), never touched that I'm starting with. I'm going to bore it .030 and put in forged pistons, have the crank cut and then balance the entire assembly (crank, rods, pistons, etc.), and use the orig rods. For the cam, I'm thinking the 744, and then 1.52 roller tip rockers on the 5C heads (that I will treat to a 3-angle grind and mill to 96 ccs). I could use the 15's on the motor but I want the bigger valves and lower compression. BTW, the heads are currently 101 cc, how much to I need to mill to get to 96, I've heard .005 for every cc, so do I want to mill .025? (I'm sure my machinist will know, but I figured if I knew up front...) It has 1 5/8" 4 tube headers into 2.5" dual exhaust through flowmasters. Anyways, back to the engine, the intake is the one that came on this engine, which I beleive was the same as the RAIII intake. Feel free to make any suggestions on the rest, but my main question is on which carb to use, the Carter Q-jet that came on this motor or a 77 800 cfm Rochester Q-jet? Would I have any problems hooking up the newer QJ to the older intake, like the choke? Any Oh yeah, the car weighs about 4050 with me in it, and the torque converter is a B&M Holeshot 2400.

Thanks for your help!

Kevin Dush
kevin@fizziwigs.com

[KevinDush]

Hello. I am soon going to begin the rebuild of a 455 for my 76 Trans Am. It is an automatic (TH400) with 3.23 gears, which is driven daily (weather permitting), with regular strip action in the summer months. With the 400 in it now I ran a best of 14.6 @ 96mph. How does this combo sound?
1970 455 (out of a Bonnie Hearse, 360 hp), never touched that I'm starting with. I'm going to bore it .030 and put in forged pistons, have the crank cut and then balance the entire assembly (crank, rods, pistons, etc.), and use the orig rods. For the cam, I'm thinking the 744, and then 1.52 roller tip rockers on the 5C heads (that I will treat to a 3-angle grind and mill to 96 ccs). I could use the 15's on the motor but I want the bigger valves and lower compression. BTW, the heads are currently 101 cc, how much to I need to mill to get to 96, I've heard .005 for every cc, so do I want to mill .025? (I'm sure my machinist will know, but I figured if I knew up front...) It has 1 5/8" 4 tube headers into 2.5" dual exhaust through flowmasters. Anyways, back to the engine, the intake is the one that came on this engine, which I beleive was the same as the RAIII intake. Feel free to make any suggestions on the rest, but my main question is on which carb to use, the Carter Q-jet that came on this motor or a 77 800 cfm Rochester Q-jet? Would I have any problems hooking up the newer QJ to the older intake, like the choke? Any Oh yeah, the car weighs about 4050 with me in it, and the torque converter is a B&M Holeshot 2400.

Thanks for your help!

Kevin Dush
kevin@fizziwigs.com

[Old Man Taylor]

The old H-O book indicates 0.0063" per CC. Your combination sounds good, but as always it depends on where you want to optimize, or conversely, where you want to compromise. Your selections lean more towards a good street machine. You could go a little more radical on the cam if you wanted to focus more on performance. If you are set on the "H" cam, make sure you get an updated version, not a factory duplicate. Oh yeah, use ARP bolts with your stock rods.

------------------
Jim

[Chiefpontiac]

Use the original '70 Q-Jet for now. The choke mechanism will bolt up and you can drill out the small throttle cable stud and replace it with the larger stud. Your engine will be able to use more cfm than the '70 Q-jet can deliver, but, the '77 800 cfm carbs need minor modifications to be undo the lean factory settings. Also, just because the '77 carb is capable of 800 cfm, it might be adjusted to flow less. Check the angle on the secondary air valve flaps. To provide 800 cfm, the flaps need to open to almost 90 degrees.

[KevinDush]

Hey everybody... well, now for the longest time I was set on the 744 cam, but I've decided that maybe I'd go a little more as I'd like a little more "oomph" and I'd like a little lump in my idle. So, I'm thinking of going with Nunzi's 2041HL (222/232@.050 with .450/.470 lift @1.5, LSA is 114, CL is 109, Overlap is 73 and 3 degrees are ground in, thanks Rocky!).

As for an update, I got the carb back (looks very nice), and I should be getting everything else back from the machine shop soon, and will begin putting everything together within a few weeks. Now, as I said, I was all hunky dory with the 744, but then started looking at custom grinds (I don't mean necessarily custom ground, I just mean non-OEM grinds). Well, after doing quite a bit of studying about camshafts (reading from Jim Hand's street machine articles mainly), I've kind of decided on Nunzi's 2041HL, though I will check with him & let him make the final decision. So my question is this, what do you think that I will run in the quarter mile with this set up? Compression will be in the area of 9.3:1 or so. The drag race program that I downloaded seemed rather innaccurate to me as I set it up w/my current combo (400, 068 cam, etc) and it had me running in the mid-13's whereas in reality I'm running 14.6. So, what do you think? Suggestions? Have at me. And thanks to all on this board, it truly is a great source and I read just about everything (that's where I got the idea for the cam :-).

Later,
Kevin F. Dush
kevin@fizziwigs.com

[Will]

Kevin, your combo sounds pretty good at this point. That cam will be pretty tame in a 455 and make a really broad torque band. IF you can get traction, you should easily be in the high 12s with it, but traction is always hard to come by in the 2nd gen F-bodies. I'm going to be stepping down to a cam very similar to what you're using in my 400. Currently I'm running a larger cam than that and running traction limited 13.7s in warm air on street tires. The slightly smaller cam will build more torque throughout the RPM range. In a 455 that cam will really make a lot of torque in the low and midrange RPMs. Hope you've got a good budget for rear tires!

[455ho]

Kevin, I recently put the 2041HL in my 71 455 ho T/A. The motor was stock until I changed the cam and also had Nunzi do head work on my stock 197's. That along with 1.6 rockers ( also from Nunzi ) has really woken my car up. I am really pulling at around 2600 rpms to easily 5400/5500, whereas before with the stock 068 grind cam I was probably making peak power around 4700. I recently bumped the timing to 18/40 total and just completely ruined what I have initialy done. After speaking with Nunzi I now realize that I should only have about 36 degree total advance. My project this weekend is to redo the timing and put stiffer springs back into the distributor, after that I want to put the car on the dyno to see how much hp I increased from my 300 rear wheel hp before the cam swap and head work. I would highly recommend the 2041HL and any other recommendations that Nunzi and Rocky Rotella have to offer. I'll let you know how the car dyno's and the 1/4 performance if it every stops raining here in New Jersey. Good luck.

[PONTIAC DUDE]

I know your talking engine & carb, but noticed your running 1 5/8 headers. Change them. The 455 can use the 1 3/4 tubes. Hedman makes them. BIG difference in power gain. now you can go back to your carb combo. Later. http://sites.netscape.net/pontiacdude428/homepage.

[KevinDush]

Thanks everyone for the replys! Pontiac Dude, I'm not looking for carb suggestions anymore... that post was made over 2 months ago, I just didn't want to bother making a new post just to talk about my engine again, so I replied w/an update & more ?'s. I appreciate any and all suggestions about any aspect of my set up.

Thanks again!

Kevin F. Dush
kevin@fizziwigs.com

[Gach]

Quick question, what did those heads cost you from Nunzi, and how much was the cam?

[KevinDush]

Also wondering about pushrods... just get the stock replacement type (from say Crane that are like $27) or do I need to get the chrome moly pushrods ($120-ish If I remember right)? And how about a suggestion on valve springs? If I'm getting the cam from Nunzi should I just ask him? Will he have them? Thanks,

Kevin F. Dush
kevin@fizziwigs.com

[This message has been edited by KevinDush (edited 04-29-2000).]

[Tim Corcoran]

Kevin, Since you have a rather mild cam your stock push rods should work ok. I suggest that you check for proper valve train geometry though. Also if you change your valve springs (good idea) make sure you get someone to set your seat pressure (95 to 115)or you could have big trouble wiping out cams.

Tim Corcoran

[Rocky Rotella]

Geeez guys, thank you all for the complements. But I did make one mistake, Nunzi's cams have 4 degrees advance ground in, not 3. Damn typos. When you get the cam, it'll have the LSA and advance etched on the end. "NUNZIS 068HL 113+4" is on both of our 2041HL's. Nunzi's cams run $135 for the cam only. I'd suggest getting the standard hydraulic lifters from Summit or Jegs. They are made by Crane and run for around $40/set. I have used those lifters with the cams and never had a problem. Don't be fooled into using anti-bleed, anti-pump up or variable rate lifters with these cams. These cams offer plenty of low end torque and vacuum. The drivability of them is outstanding. I'd also suggest Comp 995-16 springs. They are dual springs that are rated at .640" lift with not a ton of spring pressure to hammer the seats and kill the lobes. These are available from Summit and Jegs for around $90/set. On my 4X's I installed Ferrea valves, Comp springs, Comp retainers, Comp locks and Comp Seals and assembled without any real measurements. I have yet to have any problems. Stock pushrods will suffice as well. I asked Nunzi about this directly and he said that stock pushrods will be able to withstand what ever hydraulic lifters can put out. Thanks again guys and I am always willing to help with what has worked for us. Feel free to bug me, I love it.

[Tim Corcoran]

Pontiac Dude,

I wouldn't speak to fast about a 455 requiring 1-3/4 headers. I have a local racer friend with a roller camed 455 that recently ran an 11.02 in his 67 GTO. He is using 1-5/8 headers and tried a set of 1-3/4's and there was no change in performance so he went back to the 1-5/8 headers. I also am running Hooker 1-5/8 headers on my 65 LeMans 455 solid cam combo (11.20's) and soon will be trying the Hooker Super Comp's on my car. I will report what my findings are.

Tim Corcoran

[KevinDush]

Tim, Thanks for the comments and the example about the headers. I'm glad because I just bought the headers and wasn't looking forward to sending them back to get different ones. As for the valve train, I'm going to again go as per Rocky's suggestion since he's run an almost identical setup. Thanks all! I can't think of anything other ?'s right now, but if you have any suggests please let me know. Well, for now all I can do is wait for the engine to get back from my machinist. I'll let you know how it turns out.

Later,
Kevin F. Dush
kevin@fizziwigs.com

[Bob Dillon]

Kev, one thing. The '70 motor was nominally over 10:1. If you cut the heads it'll be more. Are you running pump gas in this? I think you're skirting the line on compression. Anyone else agree?

------------------
Always remember, the state's
psychiatrist is NOT your
friend.

[KevinDush]

Bob,
If you read my first post on this thread where I explain my combo, I state that I have a '70 455, however I also state that I'm using 5C heads (from a '75 400) milled to 96cc's which w/a .030 over bore, .041 head gasket, and 6.6 cc valve releifs, my compression ratio should figure out to be somewhere between 9.2 and 9.5 (not sure of deck height yet and I'm unsure whether I'll have it zero decked).
Thanks for showing concern though.

Later,
Kevin

[Bob Dillon]

Sure, Kev. Just for your information, I'm running 6xs on a zero deck 455. Compression figures to 9.4:1, and it runs fine on pump gas with 10 degrees initial. Good luck with the combo. Bob.

------------------
Always remember, the state's
psychiatrist is NOT your
friend.

[455ho]

Kevin ran my car ( 71 T/A ) at Pontiac Day, Englishtown. Car ran 13.6 @ 109 mph - through exhaust ( with stock manifolds ) on street tires. My 60 ft. times were horrible ( 2.6 - 2.8 ). Nunzi's cam/head work really woke my car up.

[KevinDush]

455HO, congratulations on the run! And thanks for the info. For those of you that are good w/figuring out how quick a car will run from the MPH, how fast should 455HO's T/A be able to run w/traction?

Thanks again!
Kevin F. Dush
kevin@fizziwigs.com