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I have been studing my options almost non stop since I pulled my 400 out of the car. I have had a lot of input from people here and on Classicalpontiac.com and I appreciate them all. I am sorry if I am seeming to repeat myself. My engine choices at this moment are building a 455
for a cost of 1500-2000 dollars for shortblock reusing my 6x heads at 87 ccs and 1 5/8" headers backed by 4 speed and 3.42 rear gears. my other choice would be to replace the bearings in my 400 and clean and freshen up with new pistons cost about 800-900 dollars or do bare min and just replace the bearings and flush oil galleries with diesil fuel with oil pump priming tool. for about 350 dollars. I probably will not take the cheap route. What ever my chioce I will be stuck with it for a while. My current specs for the 455 as I ran it on my desktop dyno are 462 cid, 9.8 comp, head flows 220cfm intake and 150 exhaust cam .470 lift intake and exhaust basically a RA4 grind I think from wolverine duration 308/320 and 231/240 @.050. dyno figures are as follows RPM;tq;hp: 1875;405;144: 2375;437;197: 2625;447;223: 3375;470;302: 3875;472;348: 4375;447;372: 4875;406;377: 5375;349;357: 5625;302;323 the 400 specs are as follows 412cid 9.2 compression same heads cam is comp cms extreme energy 268 with 224/230@.050 with .477 and .488 lift on 110 lobe centers same format 2000;371;141 2250;388;166 2750;407;213 3250;420;260 3750;430;307 4500;409;350 5000;376;359 5500;332;348 5750;298;327 I might coul dgo with the cam Jim Hand uses but I would probably have to change valve springs and have the heads milled for the new springs and that adds expense. Goals at mid 13's or Better... low 13's ?? high 12's. You get the idea always want more. I Just finished the restoration of this car and still have bills left over from that so I am really looking at it from a bang for the buck angle also. I want to make the right choice though and be happy for the next couple or three years till maybe I will have the thing paid off. I then would be ready to really turn up the heat. I need it to be able to be driven on trips and have power brakes and AC. I have not figured any upgrades in the cooling system to this either the 400 was staying cool and the radiater is not a 4 row maybe a 3 Thanks |
I have been studing my options almost non stop since I pulled my 400 out of the car. I have had a lot of input from people here and on Classicalpontiac.com and I appreciate them all. I am sorry if I am seeming to repeat myself. My engine choices at this moment are building a 455
for a cost of 1500-2000 dollars for shortblock reusing my 6x heads at 87 ccs and 1 5/8" headers backed by 4 speed and 3.42 rear gears. my other choice would be to replace the bearings in my 400 and clean and freshen up with new pistons cost about 800-900 dollars or do bare min and just replace the bearings and flush oil galleries with diesil fuel with oil pump priming tool. for about 350 dollars. I probably will not take the cheap route. What ever my chioce I will be stuck with it for a while. My current specs for the 455 as I ran it on my desktop dyno are 462 cid, 9.8 comp, head flows 220cfm intake and 150 exhaust cam .470 lift intake and exhaust basically a RA4 grind I think from wolverine duration 308/320 and 231/240 @.050. dyno figures are as follows RPM;tq;hp: 1875;405;144: 2375;437;197: 2625;447;223: 3375;470;302: 3875;472;348: 4375;447;372: 4875;406;377: 5375;349;357: 5625;302;323 the 400 specs are as follows 412cid 9.2 compression same heads cam is comp cms extreme energy 268 with 224/230@.050 with .477 and .488 lift on 110 lobe centers same format 2000;371;141 2250;388;166 2750;407;213 3250;420;260 3750;430;307 4500;409;350 5000;376;359 5500;332;348 5750;298;327 I might coul dgo with the cam Jim Hand uses but I would probably have to change valve springs and have the heads milled for the new springs and that adds expense. Goals at mid 13's or Better... low 13's ?? high 12's. You get the idea always want more. I Just finished the restoration of this car and still have bills left over from that so I am really looking at it from a bang for the buck angle also. I want to make the right choice though and be happy for the next couple or three years till maybe I will have the thing paid off. I then would be ready to really turn up the heat. I need it to be able to be driven on trips and have power brakes and AC. I have not figured any upgrades in the cooling system to this either the 400 was staying cool and the radiater is not a 4 row maybe a 3 Thanks |
Any cam over 460 lift is getting you into "coil bind" territory on 6X heads. Go with the 455 (there's no replacement for displacement) on the street. More bottom end punch. Stay with a cam with 110-112 lobe seperation angle for good vacuum without the cost of quick bleed lifters. Your combo sounds good.
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The 400 is dead Im afraid. I Finished tearing it apart today. I had other problems that had not matured. I had scrathes on two cylinders from stuck or broken rings I don't know but since the block is .060 over its done I guess. I will set it aside for extreme hard times like when pontiacs are goen from the market and sleeving is the only choice on a rebuild. I am investigating
455 rebuilds now or a rebuilt shortblock for 900 bucks from my local parts store. I am incuraged by the machine shop though he quoted me 475 labor to bore/hone,grind/polish crank check for cracks/ rebuild rods and shotpeen/ magnaflux, Balance and press pistons to rods. It was cheaper than I first thought he would be so I might be able to afford to rebuild the thing Right !!! He also said he woul ddo a set of heads for 165 new guides and seats ground. so I might pull my 96 heads out from under the bench if I can scrap up th ecash that would cover the compression issue ! They will need new valves though ! oh I have crane 99840-16 springs now 1.57 installed at 90lbs and 1.100 open at 280 coil bind at .935 . can I go higher than .470 coil bind is at about .6 [This message has been edited by 77TA (edited 12-28-1999).] |
A 455 with 6X heads is a good combination. I like Comp Cams version of the Ram Air IV cam. Use good valve springs that allow .500 lift. Crane makes a nice drop in spring that fits the bill. With the right gearing and convertor, you should run low thirteens on radials and 12s with good tires.
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A good driver and clutch with the four speed!
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