350+hp recipe? Hey guys. I need some help.... I am about to build a 455 motor for my Buick, and I would like to get about mid-high 300hp. This motor will not be built for racing purposes. I would like the car (1976 Limited, 4dr HT) to be a weekend cruiser with sufficient power. Here are my plans: High(er) Compression Pistons: Not sure as to what C/R to shoot for. I was thinking 8.5:1, or 9.0:1 cast pistons. (Will probably do .030" overbore) Camshaft:I was looking at the cam selection from TA. I would ideally want a cam that will improve low end, and mid range hp/tq figures while retaining a smooth idle. Does anyone have any first hand experience to provide feedback suggestions? Intake manifold:TA SP1. Carb: It seems that the Holley Q Jet is really popular. Any input here is welcome. I dont know much about carbs. Cylinder Heads: I was planning on having the heads ported by a local guy. I was referred by a member of this site, and have been told that this guy knows Buicks really well. Headers/Exhaust: TA competition headers seem alright to me. The headers will lead to a 2.5" dual exhaust system. I am very open to any advice as far as selecting parts. I am new to this motor, but I know it has lots of potential. I would like some guidance to make sure I do things right the first time. Thanks Langston
I'm assuming you have a 76 motor. Your intake/ Exhaust Combo sound good, and will easily support your goal. However you need to look between the intake and exhaust, Your heads, and make most improvements there. In this case, replacement. 75-76 heads work best as winter weight only. Try to find heads from the 67-71 range. 67-68 Big port heads optimum. 69-71 are higher compression heads, and offer a much better chamber design. Bowl blendning and some clean uo will net considerable gains. I like the looks of the TA413 cam, or something comparable. I'd run a fully re-worked q-jet. It is a great carb in stock form, but when It comes to performance motors, it like any carb will need some serious tuning.
For low 400's HP you could stick with stock intake and exhaust manifolds, or port them for even more power! Headers increase "cabin noise" and are more leak prone. If you do decide to go after-market I'd stick to a dual-plane intake for your application, and if you must have headers check out TA's shorties. I'd stay away from a "full port job"; you want to increase flow but also keep port velocity very high. So "bowl work" / "short turn radius work" is key, kinda like a www.gesslerheadporting.com level 3 head. Cam wise I'd look at TA's 212(218-230 at .050) and wouln't go bigger than the 290-94(226-235 at .050) on a 114 centerline w/ 6 to 8 degees of advance. P.S. The early heads are better(more power/less detonation prone). Just my 2 cents Steve Walsh
Thanks for the advice. I'm glad to see I was on the right track somewhat. It is tickling to actually be able to get power out of this motor. With my saturn motor, I would have been stretching to get 300whp...turbocharged. I will look into getting some early model heads.
with 70-71 heads, some port work and a good 3 angle valve job, and somethink like a 118 cam,and around 9.5 to 1 comp.,you can make that kind of power with the stock intake and manifolds, the key to these moter is in the heads, put more money in your heads before you go to an sp1 or headers.
Low end torque, Low RPMs mostly, heavy car, not racing intended leads me to think along the lines of one of the towing cams and a dual plane intake. keep compression low (9-9.5) and you wont have a problem on pump gas....maybe even the cheap stuff. Get a Q-jet reworked and you''l be fine. Personally, I'd go shorty headers and dual mandrel bent 2.5" exhaust with an X pipe. Big Blocks ned to breath both in and out. Several guys have listed their "worked" iron heads for sale lately and I dont think they all sold. Do a search in the For Sale forum and track them down. Dont forget to do ALL the oiling Mods and get a GOOD timing cover and oil pump setup. Dont be upset if of you make closer to 450 hp either :TU:
Will you be digging into the shortblock to swap the pistons? I wonder how much power can be obtained by using the stock 76 short block with everything else upgraded...
I will be swapping the pistons. I want to raise the compression a lil bit. I will probably use 9.5:1, .030" over pistons. I am going to buy a spare motor to fully rebuild.
my moter in my 70 gs is a 76 block, those 76 heads are laying out in the woods behide my shop, the commbustion chambers sit about a 1/2'' higher off the piston compared to 70 heads.
Hey guys, sorry for bringing this back from the dead, but things are finally starting to get rolling. I just got my tax return, and I am ready to get this thing started! My heads will be '72 heads (72 cc) with mild port work, and 3 angle valve job. The block will be a '70 block. I will be shooting for an actual compression ratio of 10.0:1. I will be re-using the stock rods, and will have them reconditioned by my machine shop. Same deal for the crank. I will have them check it out and see if it needs to be ground any. There are about a thousand thoughts running through my mind, as I am excited about getting this rebuild started!
I would definitly plan on haveing the block decked if you want 10.0:1 compression. Good luck, and keep us posted....
Cool... sounds like fun! I would get a B4B intake and headers as your first mods. I don't know if I'd worry about decking the block on this motor. Even low compression should get you what you want. What pistons are you using? The temptation is definitely there to go crazy on a rebuild. My motor was going to be somewhat close to what you're doing with a bigger cam. Now I have stage 2 aluminum heads! It's one of those "how far should I take it" kind of things.
Might want to rethink using the SP1 intake. A dual plane intake would be better for a street only car. A T/A 413 cam would also be too much cam. I have a similar custom grind that JW put in mine. It has a nice choppy idle and needs a stall converter....... it doen't sound like what you are trying to accomplish. I run the new SP1 and it works great..... on my car. A Q-jet and an Edelbrock Perfomer would be a better setup IMO. Brian
There is an oiling mod you need to have done on a '70. The passage needs to be enlarged (not sure which one or exactly where) and in the timing cover as well. The 455 is going to provide plenty of power. Mine is a mild Tri-Sheild Perf engine with a mild cam, dual plane Performer intake and headers. It made 485hp!
is their a mismatch between water jacket holes that he needs to be concerned with on a 70 block/72 heads combo? anybody? Patton
