![]() ![]() The difference was immediate, even at idle the engine sounded crisper and revved effortlessly. The dyno operator asked what the other carb was and I told him it was a Holley- Proform hybrid 750 that I'd used on my 355, and he said lets try it. ![]() ![]() That carb didn't belong to me, so I didn't want to mess with it and off it came. I had a "good" 950 DP that we tried next, and the engine didn't like it losing 12 hp. On the dyno, I had 3 carbs to play with, so we broke it in with a decent 850 DP, and after finding that this motor too liked 34 degrees, our best pull brought us 605hp. I'm running the Comp SS rockers,1.5 and 1.6 split set. I picked up a 2925 Edelbrock Super Victor intake and had it matched up to the heads. Up top, I freshened the Motown 220 heads that came with the car, they'd been previously ported, and with new 2.08/1.60 valves, they were good to go. I got Manley H-beam rods and crank, Probe pistons, a Comp Cams roller setup and a Moroso pan and oiling system for the bottom end. I was told by several builders that with the combo I had floating between my ears I'd be over 600hp and I should really think about an aftermarket block for piece of mind, so I bought a Dart SHP block for the build. When the 355 gave up the ghost in my '68 Nova, 3150lbs,10.5x29.5 tire, full cage, ladder bar- leaf spring rear setup with 4:88 Dana 60 and a Coan glide, I started doing some research on the 400. I picked up a standard bore 509 block a few years back for a "future project". I agree with Adger in using a 400 block in a MILD bracket application. I pushed the compression at 14-1 and have 250lbs compression.but she's working and Wallace calculators show 550-565 from my slips and weight. I've read over and over.that about 600hp is safe limit of the 400. too much deck is bad,and too much timing is too. The deck clearance and timing are aimed at preventing detonation. The cement is good for bottom end but the 2" of water at top is still keeping it cool enough on methanol/injection and small radiator in our hot FL heat. The studs up top hopefully are taking the extreme pressure off the common thread cracking places. 003 on mains.035 rear.027 on rods.The deck is. Runs well and beating Big blocks costing $10,000 more than the $3000 invested and a leftover 400 block this cost me. Didn't want them loose and banging cylinder walls.The engine has about 100 passes now. We where unable to use torque plate at my friends shop 'cause his didn't fit the large 4.185 bore. Transbrake leaving at 2500 with 5100 stall convertor. Block is filled to front freeze plug holes,stock caps,studs top/bottom. EQ iron 220 23* heads, elgin1090 mech flat tappet cam,msd,and hilborn on methanol. 14.1-1 compression,scat 5.7 pro rods,eagle 3.75 crank,icon ft pistons,regular 5/64 gapped total seal rings at. 509 casting.I built it with a tight budget but am making 565hp and turning 7200. I don't think twice about using a well prepaired stock 400 block for a good mild bracket application. You would be surprised at how tight his PTC converter is. He is seen quite often in the last couple of rounds and at the winners circle. He runs foot brake/NoE as well as some 6.50/7.00 index classes and is deadly consistant with it. I've got one customer that uses one in a S/G style Monza that has Track 1 heads 11-1 compression and (FT) Eagle rotating assy, Small comp solid roller. Another issue with big SBC's (until lately) has been heads. I plan on putting it in a former Comp Street Roadster I have to run some local Index classes. I've done quite a few of them over the years and am doing one for myself at this time. Gear and converter it and keep the RPM well below 7,000 and it will make you a strong bracket engine that should last a season or two before freshening. don't treat it like a 302 SBC and try to make it an RPM king. Run a leak down on the engine before you buy it and see if it is healthy. A shop that takes the time to do the right things to a 400 block will probably be using plates. I think that is the most common complaint of the 400's when they were first being used as race engines. There can also be cracking out of bolt holes if plates aren't used. Blocks bored and honed "Without" stress plates are prone to cylinder wall distortion and bad ring seal. A shop that puts on caps and block fills will usually be doing the other thing that is a common problem with a 400 block. The block fill makes the weaker cylinder walls stronger. The caps tie the bottom end together and help hold the long stroke crank.
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