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#1
12-05-2006, 07:37 PM
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Building my First Pontiac
I am a first time poster - have been getting lots of excellent information from the site over the past few months. I'm building my first Pontiac and had a few questions and would welcome any general recommendations. Here's what I've got so far (I apologize for the wordy post)
Car is a 1976 Esprit T350auto that had 55K orig miles - all original best I could tell and in excellent shape. Pulled the 350 and going back with a 400 - looking for good low to midrange street power. Engine is 400 bored 0.030 over that I picked up from a PY member, SpeedPro Cam 214/224 112SA, hyd lifters, 1.5 flat tappet rockers, TRW pistons, stock crank and rods. I'm adding Edelbrock Perf intake, Edlebrock alum heads 72cc and new carb (haven't decided on which - leaning Barry Grant). Tore down motor and is now in shop. Block is in the hot tank today, will be honed, mic'd, polished crank, all new bearings, etc. (any need to balance ?). Also, based on my calcs I'm getting around a 9.9 CR - sound right ? Plan to replace the 2.40 rearend with 3.23 posi I picked up and keep the T350 tranny. Will the T350 handle this setup or am I setting it up as a weak link? |
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#2
12-05-2006, 07:47 PM
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Welcome to the site.
Sounds very similar to what I'm planning to build in spring. Let me know how it turns out? |
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#3
12-05-2006, 07:49 PM
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Quote:
Regarding the T350... Pontiac always put a T400/M40 behind a 400 ci... I assume they did that for a reason.(otherwise, they'd be wasting their money).. Note they did this with stock motors.. the motor you describe should run much stronger than stock... You'd be well advised to upgrade the trans... especially since you've got it all apart now.... |
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#4
12-05-2006, 07:51 PM
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The T350 will hold up fine. Maybe add a Trans Go shift kit. Those heads are kinda overkill for that setup. You know you`ll have to get round port manifolds or headers for those heads? All and all, i`d add a little more cam if you`re gonna use E-heads.
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#5
12-05-2006, 08:59 PM
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Like Punch said, e heads maybe overkill, but will provide great flow at 3000rpm and above. If this is a strong street build I'd look for a cam with approx 220 intake (crower 60916 is proven) with a lobe separation of 112. The SpeedPro you have would be fine but certainly won't take advantage of all those dollars invested in the heads. The crower would give good power up to 5500rpm which is about the max you'd probably want to run the stock rods and crank to on a regular basis. If you haven't already got the e-heads I'd do a bunch of research on this site. The larger port sizing of the eheads tend to reduce low speed velocity which can deminish torque which is what you want with a strong street car. Jim Hand's book is pretty much a "must have" for anyone interested in building a high performance street build. The TH350 I think will hold fine, maybe just freshened up a little. The 3.23 rear will be good all round. Oh yes, I'd get the internal parts balanced and have the block zero decked while you're at it so long as it doesn't push the CR up much. Do you have any iron heads that came with the motor? Many times for street uses, these can be set up great and potentially save you a bunch...just a thought.
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#6
12-05-2006, 11:20 PM
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Fresh meat
 Another vote for Jim Hand's book - How to Build Max Performance Pontiac V8s". Well worth the admission price.
__________________
1969 GTO hard top ~ Std bore 400, '70-RA3 block, 670 heads, Bal. & Blue... M22, 12-bolt w/3:55s |
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#7
12-05-2006, 11:53 PM
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You say you want excellent low to midrange RPM performance and everything you've done adds up to that *EXCEPT* the heads.
The Edelbrock heads are not bad heads, and your engine should be a very strong performer, but the heads are total overkill for your goals. With that size cam you could easily have just run stock heads at 9:1 compression and maybe gotten even more low RPM torque out of it due to the higher port velocity present in the smaller ports. Also, the standard Edelbrock Performer intake doesn't flow all that well, it's choking those heads. An RPM intake would be a much better match though you'll have problems fitting that under your Esprit's hood. Maybe a Torker II would be a good middle ground, especially if you up the cam. If you really want to take advantage of those heads, consider a cam with about 15 degrees more duration @ .050" and some high ratio rocker arms. Of course you'll then have less low RPM torque but the increases in the midrange and upper RPMs will more than make up for it if you choose the right converter. For the best of all possible worlds, I'd be looking at a custom solid roller from Comp based on the Xtreme energy street lobes. Without looking at the exact numbers in their catalog, I'd be looking to have a cam ground with approximately 226 @ .050" on the intake side and 230-232 on the exhaust side with a 110 lobe sep and use whatever rocker ratio is needed to get to about .580-.600" lift after subtracting lash. Such a cam would idle like a pussy cat with a distinct performance lope, plenty of vacuum, and tear your head off in the midrange. Use Crower rollers with the HiPPO option for the street. Also, for low end power you really want to stay conservative on the header primary pipe sizing. It used to be that the smallest you could get in a round port configuration were 1-3/4" primaries. I dunno if that's still true or not, but you'd definitely be better off with some 1-5/8" primary tubes if low end and midrange is your goal. Whether the TH350 lives a long life or not depends on who built it and what parts were used. They can be very tough trannies if built by the right people. I had one that I acquired in exchange for some work I did on a guy's car that had first been used in a bracket racing El Camino, then in a '69 Chevelle and eventually in my Nova. After 200K miles of abuse (behind relatively small engines compared to a Poncho) it was still going strong.
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#8
12-05-2006, 11:55 PM
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Forgot to address your balancing question: Yes!
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#9
12-06-2006, 12:12 AM
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Quote:
An upgrade to a TH400 would be nice (I would), but not entirely necessary.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/3.08 2002 WS6 Convertible LS1/4L60E/3.23 1966 VW Type 2 Single Cab Pickup 140hp 2276 1956 VW Type 2 Panel Van 36hp 1200 1957 VW Type 1 Beetle 180hp 2276 |
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#10
12-06-2006, 10:15 AM
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Guys, thanks for the input. Current heads are 101cc version which should give me CR around 7.8, right ? - doesn't sound good. What are recommendations regarding head - mill existing 6X-8's, swap 72 for 87cc aluminum (which should be right around CR of 9)?
Also forgot to mention I have purchased 1-5/8" ceramic coated Hooker Comp Headers and a 2.5" Pypes dual exhaust system as well... |
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#11
12-06-2006, 11:17 AM
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Welcome, I'd spend the money for a TH400. Had a '71 Monte Carlo once with a 350/350 combo and it ran fine together. Changed the motor to a 454 and left the 350 trans behind it....Wrong! torque monster big block ate that tranny up. I've seen them(TH350's) last with high quality internals but in general the 400 is the way to go IMO.
Good Luck, Blue
__________________
'69 GTO Convertible-Liberty Blue/Parchment '71 Grand Prix SJ 455-Triple Black-Sold '84 Corvette-Bronze/Bronze |
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#12
12-06-2006, 11:36 AM
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If going aluminum then you can get away with 10-10.5:1 comp (Keep the 72cc's). 9.5:1 max with iron heads.
Compression calculator and various others. http://www.sdperformance.com/calc.php
__________________
Derek B. Current best: 11.97@110 1.65-60' !!! '74 ventura,  (Fired july 14/06) '74 462 4-bolt (9.5-1), SCAT, Ross, T-II w/850DP (shaker455), TH350, Conti 10'' 3800, Supercomps, Magnaflow, 3'' Pypes, 3.73's, 28x13.5-15 ET streets.1970 Beismeyer 17' flatbottom vdrive, 11.8:1 455P, ported heads, dual Qjet tunnel ram. 
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#13
12-06-2006, 11:36 AM
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Quote:
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#14
12-06-2006, 12:28 PM
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Quote:
the 350 will be fine if built properly, go with a performer rpm intake and qjet also KRE d ports would probably be a little better for your set up and they would save you some cash money |
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#15
12-06-2006, 02:54 PM
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JackMonkey is right - looks like I mismatched heads with headers. What I'd like to do since I'm really looking for decent street power is return the heads (then I'd be able to feed my family again) and mill the stock 6X-8's to ~9.0 CR. Is this doable and/or recommended practice ? Also, the shop is really good but doesn't do many Pontiacs - wanted to know if he could angle mill...
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#16
12-06-2006, 03:48 PM
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You might want to consider zero decking the block and using 6x-4 heads. If you milled the heads a bit and used TRW 2262 pistons, you could get the compression into the 9's easily enough. With 6x-8 heads, you pretty much need to use a pop up piston to get the compression up there. When I built my 400, I used 2262 pistons with an additional 6cc dish and a set of 1968 #16 heads that measured 71cc. With a .015 dech height, my comp is at 9.6
Chris |
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#17
12-06-2006, 05:24 PM
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Chris - excellent idea - especially since the 350 I pulled out of it has 6X-4 heads ! Thanks.
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