Boosted 400 block strength?

[octusis]

Good afternoon, from my research and word of mouth everyone says the 400 block is the go-to block for mopar big blocks in terms of capable power. However I have not seen much about people running boost through these and how well they hold up. I’m looking at doing a stock stroke, turbo, forged internals, Holley efi, alum heads, girdle (possibly) 400 to hopefully see around 800-900hp street driven (maybe occasional track). I will keep rpm’s below 6000 aswell. Is this something that’s too much to ask of these blocks even partial filled? If so what are the limits?

My second option is a 3rd gen hemi I already have some parts for, but would love to keep oldschool as much as possible.

Any comments or advice would help me significantly. Thanks for your time

 

[diesel_lv]

Room is a premium under most big block Mopar hoods, that's why you don't see a lot of turbos. Ideally, 14lbs of boost will double whatever hp your engine is putting out n/a. 14lbs takes a little bit of extra engineering, intercooler or meth injection. Using a blowthru throttle body injection helps a lot though w cooling the intake temps w the evaporative effect of the fuel. Fuel becomes an issue too, "Very" efficient heads, and I mean "Very", can handle 91 octane at 14lbs of boost. So using that much boost, you need 400-450hp n/a. Can a 400 handle it? Yes, if using forged rotating assembly and studs etc. Unless you're WOT all the time, the engine is cruising in vacuum, not boost.

 

[octusis]

Room is a premium under most big block Mopar hoods, that's why you don't see a lot of turbos. Ideally, 14lbs of boost will double whatever hp your engine is putting out n/a. 14lbs takes a little bit of extra engineering, intercooler or meth injection. Using a blowthru throttle body injection helps a lot though w cooling the intake temps w the evaporative effect of the fuel. Fuel becomes an issue too, "Very" efficient heads, and I mean "Very", can handle 91 octane at 14lbs of boost. So using that much boost, you need 400-450hp n/a. Can a 400 handle it? Yes, if using forged rotating assembly and studs etc. Unless you're WOT all the time, the engine is cruising in vacuum, not boost.

It’s came across my mind potentially doing a light stroker to get n/a hp up but I don’t want to side load too much what are your thoughts on that? For heads I plan on getting a set of trickflows whatever combo I end up with I’m shooting for 9:1-9.5:1 comp.

 

[dvw]

You'll be fine. We've run up to 22psi on a stock block cast crank 360 for years. Just keep the timing reasonable. Made enough power to go 9.55@141, 3750lbs
Doug

 

[diesel_lv]

It’s came across my mind potentially doing a light stroker to get n/a hp up but I don’t want to side load too much what are your thoughts on that? For heads I plan on getting a set of trickflows whatever combo I end up with I’m shooting for 9:1-9.5:1 comp.

I'd shoot for 8.5-9:1. You can typically keep timing in until about 3lbs of boost n then start pulling 1° per lb. Some people go extremely safe n start of at 1lb n 1°. I've got a Ford 4.6 4v aluminum engine that only needs 23° total timing n/a to make peak hp, "Super" efficient heads. At 8.5:1, air/water intercooler using 70° river water, blowthru carb, I run 14lbs on 91 octane and don't pull any timing. 710hp at the crank. But that's an entirely different kind of head n cooling system.

 

[67_satellite]

Good afternoon, from my research and word of mouth everyone says the 400 block is the go-to block for mopar big blocks in terms of capable power. However I have not seen much about people running boost through these and how well they hold up. I’m looking at doing a stock stroke, turbo, forged internals, Holley efi, alum heads, girdle (possibly) 400 to hopefully see around 800-900hp street driven (maybe occasional track). I will keep rpm’s below 6000 aswell. Is this something that’s too much to ask of these blocks even partial filled? If so what are the limits?

My second option is a 3rd gen hemi I already have some parts for, but would love to keep oldschool as much as possible.

Any comments or advice would help me significantly. Thanks for your time

View attachment 1356603

Been doing it for the last 5 years with one built as a 470.I run 2 of the ebay GT 45 knock-offs, but 1 would work for a 400 at modest power levels. Look up some of the Richard Holdener vids on Youtube, he has run that turbo on just about everything. Look for the vid where he ran twins on a 468 B.B.C., It was like 15 p.s.i. boost and only 6 lbs. back pressure in the exhaust. One will support just shy of 800 h.p., but becomes restrictive on the hot side on larger c.i. engines. I ran a single on the 383 I had in the car previously with good results. The 383 was a high milage, cast piston deal out of my old d.d. Newport. It lived with 15 lbs,20 degrees of timing, on 91 octane for 6 years. I still have it for a backup should a tragedy occur with the 470. The 470 is a Edelbrock head, 10:1 comp., half fill with a homemade 3/8" girdle on E-85. Just a late 1975 block, nothing special. Started with a 750d.p. blowthrough but have since gone to a Sniper set-up. I have had it as high as 17 lbs. of boost,but run it at about 12 most of the time. Don't get greedy trying to get an extra 5 h.p. cranking in more timing, and they will live a long happy life.

 

[furious70]

Doing a stroker likely forces you into more expensive turbos that wouldn't be necessary. Still today the common turbos are designed for low cfm high boost (diesels and 4cyl), forcing you to buy more expensive turbos to match a big inch V8.
I also ran 12psi on a 8.8:1 fuel injected cast piston 383 and it was fine. I did some small upgrades and now have a 9.25:1 forged piston 383 with lightly ported heads at 7psi, still getting to know it. Water injected not intercooled. Intake temps drop 40* when the water hits.

 

[67_satellite]

Doing a stroker likely forces you into more expensive turbos that wouldn't be necessary. Still today the common turbos are designed for low cfm high boost (diesels and 4cyl), forcing you to buy more expensive turbos to match a big inch V8.
I also ran 12psi on a 8.8:1 fuel injected cast piston 383 and it was fine. I did some small upgrades and now have a 9.25:1 forged piston 383 with lightly ported heads at 7psi, still getting to know it. Water injected not intercooled. Intake temps drop 40* when the water hits.

GT45 T4 V-Band 1.05 A/R 98mm Huge 600Plus HPs Boost Upgrade Racing Turbo charger | eBay I feel like a chump, I bought mine when they were $249. They work and are anything but expensive. Take them apart and clean out any chips, reassemble and go.

 

[furious70]

That is a small hot side for a single on a big block, ok for 383

To elaborate, those sorts of turbos have ridiculously big compressors and too small turbines generally for big blocks. They are a mismatch.

 

[66chargerpat]

What are yall running for exhaust manifolds for the b/rb engines? Thanks in advance

 

[furious70]

I used these, the only ones that can be flipped upside down. From van/RV chassis, but not RV engines

 

[furious70]

 

[Sweet5ltr]

Good afternoon, from my research and word of mouth everyone says the 400 block is the go-to block for mopar big blocks in terms of capable power. However I have not seen much about people running boost through these and how well they hold up. I’m looking at doing a stock stroke, turbo, forged internals, Holley efi, alum heads, girdle (possibly) 400 to hopefully see around 800-900hp street driven (maybe occasional track). I will keep rpm’s below 6000 aswell. Is this something that’s too much to ask of these blocks even partial filled? If so what are the limits?

My second option is a 3rd gen hemi I already have some parts for, but would love to keep oldschool as much as possible.

Any comments or advice would help me significantly. Thanks for your time

View attachment 1356603

Street driven, '800 - 900' HP BBM, and all this power below 6,000 RPM?

Won't likely be on the street very long at that power level (12 - 14 PSI), but yes, the 400-blocks offer a great base for a max-effort build. My friend runs one in a dart, has had great luck with a 451" turbo setup. Then again, he went through a few crankshafts in the process to get to this point.

I ran a BW T6 S475 on a 440 RB. 6-8 PSI. As you can see now, I have a 470" low-deck. Your first attempt will be a test run if you run it hard, there is no way I would do it again without some form of EFI (MPFI preferably).

I'd highly recommend a N/A 470" - 512" low-deck, with a TF-270s & Max Wedge style manifold. Can easily make north of 625-HP N/A with 500" (pump-gas, 9.5 - 10:1 CR) and be completely dependable, year after year. Spray it to 750 at the track on race fuel.

 

[octusis]

Been doing it for the last 5 years with one built as a 470.I run 2 of the ebay GT 45 knock-offs, but 1 would work for a 400 at modest power levels. Look up some of the Richard Holdener vids on Youtube, he has run that turbo on just about everything. Look for the vid where he ran twins on a 468 B.B.C., It was like 15 p.s.i. boost and only 6 lbs. back pressure in the exhaust. One will support just shy of 800 h.p., but becomes restrictive on the hot side on larger c.i. engines. I ran a single on the 383 I had in the car previously with good results. The 383 was a high milage, cast piston deal out of my old d.d. Newport. It lived with 15 lbs,20 degrees of timing, on 91 octane for 6 years. I still have it for a backup should a tragedy occur with the 470. The 470 is a Edelbrock head, 10:1 comp., half fill with a homemade 3/8" girdle on E-85. Just a late 1975 block, nothing special. Started with a 750d.p. blowthrough but have since gone to a Sniper set-up. I have had it as high as 17 lbs. of boost,but run it at about 12 most of the time. Don't get greedy trying to get an extra 5 h.p. cranking in more timing, and they will live a long happy life.

View attachment 1358022

View attachment 1358023

That’s fricken awesome, do you get a lot of lag or are they alright for your 470? I would prefer to run smaller twins rather than one for the ease of piping and how my engine bay is currently set up. If I kept it stock stroke or went 451 stroker would a 1.05 a/r likely be OK or should I think about going a little smaller? Also what kind of system are you running for water injection? Thanks for the info

 

[octusis]

Street driven, '800 - 900' HP BBM, and all this power below 6,000 RPM?

Won't likely be on the street very long at that power level (12 - 14 PSI), but yes, the 400-blocks offer a great base for a max-effort build. My friend runs one in a dart, has had great luck with a 451" turbo setup. Then again, he went through a few crankshafts in the process to get to this point.

I ran a BW T6 S475 on a 440 RB. 6-8 PSI. As you can see now, I have a 470" low-deck. Your first attempt will be a test run if you run it hard, there is no way I would do it again without some form of EFI (MPFI preferably).

I'd highly recommend a N/A 470" - 512" low-deck, with a TF-270s & Max Wedge style manifold. Can easily make north of 625-HP N/A with 500" (pump-gas, 9.5 - 10:1 CR) and be completely dependable, year after year. Spray it to 750 at the track on race fuel.

EFI is definitely going to be one of the first things I get. I’m thinking Holley terminator entire engine control setup it seems like they are very popular and work well for most. The only reason I said I didn’t want to rev over 6k is because I’ve seen not so good things at BBM over 6k, everything I’ve seen thus far is to keep rpm’s and timing down.

 

[diesel_lv]

That’s fricken awesome, do you get a lot of lag or are they alright for your 470? I would prefer to run smaller twins rather than one for the ease of piping and how my engine bay is currently set up. If I kept it stock stroke or went 451 stroker would a 1.05 a/r likely be OK or should I think about going a little smaller? Also what kind of system are you running for water injection? Thanks for the info

You need to go to Garrett turbos and look at the maps n do it the right way. Don't have to buy one of their high priced turbos, but size it correctly according to volume, hp etc.... don't be guessing.

 

[dvw]

My sons stock block and cast crank 360 has been beat on and raced for years. It did nip a piston last year after 100's of passes. Many over 20psi. Going back together now. The engine is now going in a Duster.
Doug

 

[TrackPack]

400 block at 800-900 hp = cracked main webs.

 

[octusis]

Since I been hearing mixed things with about power levels. Has anyone had any experience with Gen III hemi block strength? They’re cross-bolted like the Gen II hemis and they seem to be pretty beefy. I really would rather keep it old school but it may be a temporary thing until I can afford an aftermarket block.

Thanks for all the extremely useful information so far!

 

[67_satellite]

Since I been hearing mixed things with about power levels. Has anyone had any experience with Gen III hemi block strength? They’re cross-bolted like the Gen II hemis and they seem to be pretty beefy. I really would rather keep it old school but it may be a temporary thing until I can afford an aftermarket block.

Thanks for all the extremely useful information so far!

If you're starting from scratch,a 3rd. gen. Hemi would be a good way to go. Much stronger block,good heads readily available,less weight ,aftermarket support, etc..etc. A good first step would be to learn all you can on the subject of turbocharging. Corky Bells book Maximum Boost was pretty good. Hugh Mcinness(spelling?)also had one but it's older.If you want to use the cheapo ebay models I run, I would use 2 for a 451.