# 400 build recomendations



## algershick (Oct 24, 2016)

Greetings! I just purchased a 1967 400 out of a full size car and am looking for some advice on my build. I've disassembled the engine and my bores measure right about 4.120. I did discover 3 broken pushrods (2 in the lifter valley, 1 in the oil pan) and someone replaced them without pulling the broken pieces. :surprise: This engine has GTO exhaust manifolds, a Carter intake maniofld, and 061 casting open chamber heads. 

My goals are to build an engine that can be daily driven but still blow the tires off when I want. I plan on building an OD auto transmission and I've got 3.42 gears out back. With the right cam, is 400ish HP achievable with my combo? I'd like to use the factory intake if possible, but will it hold me back vs a QJet manifold? What compression ratio should I be shooting for, 9.5 or so? I already bought a set of forged connecting rods as I've read the factory cast rods are unreliable.

I really appreciate your input, thank you.

Austin


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## bigD (Jul 21, 2016)

Don't think you mentioned what car this engine is for. A '67 GTO came with a Q-jet. If you want a correct number intake, for a '67 GTO, you'll have to buy a '67 Q-jet intake. If numbers don't matter, any '68-'72 Q-jet intake would be a good choice. Most any GOOD Q-jet will work. If you want it to look correct, you need a '67-'70 Pontiac Q-jet without the big "smokestack" vent.

If you don't care about the exact look of your carb, then there are lots of choices. There are some early '70's 455 Buick carbs that are 800cfm, & have the front inlet like a Pontiac. There are later '70's 403 Olds carbs that are 800cfm & have the front inlet and the desirable APT feature, but a small vent. 

The '76-'79 Pontiac Q-jet is 800cfm, front inlet, & APT, but has the big vent, which requires a hole for it in the air cleaner base. One of the best builders of Q-jets in SMI. But, there are lots of sources for rebuilt Q-jets, some good, some not so good. 

SMI Carburetor Street Performance Rochester Quadrajet 800CFM Buick, Oldsmobile and Pontiac Quadrajet 4BBL SMI- Sean Murphy Induction

Everyday Performance Rebuilt Quadrajet Carburetor Store ~ Quadrajet Carburetors for Sale

If you don't mind doing a little extra fuel line plumbing, and having a side inlet, a Chevy or Edelbrock Q-jet will work. Ebay always has several rebuilt Edelbrock Q-jets for sale. One advantage they have is that they were made a lot more recently that the GM Q-jets. I think they were still being made in the late 1990's.

http://www.carburetion.com/Rochester.asp


"... With the right cam, is 400ish HP achievable with my combo?..."

It is POSSIBLE. BUT, at 9.5 CR, it is a LOT easier to make 400hp with a stroker assembly. And, since those heads are not the correct GTO heads, I'd buy a cheap set of 6x-8 cores and have 'em built correctly, with stainless valves, bronze guides, good seals, & 7/16 studs.

http://butlerperformance.com/i-2459...-400-block-4-250str.html?ref=category:1234863

If you decide to stay with your stock 400 stroke & 061 heads, you'll need dish pistons. Icon has a good 400 piston with a 14cc dish. The part number is IC891.

https://www.rpmmachine.com/shop/index.php?l=product_detail&p=6218

http://www.cnc-motorsports.com/icon-ic891-030-forged-dish-pistons-4-150-bore.html

But, if you want less compression, you can buy custom pistons with any size dish you want. 

Len Williams sells a crate pump gas 400, which he says will make aprox 385hp. So, a build similar to it should make at least 350hp, and probably a little more, depending on your cam, heads, & CR. 

http://lenwilliamsautomachine.com/400_Long_Block.html

He builds a pump gas 455 which will easily make 400hp, with around 500ft lbs of torque.

http://lenwilliamsautomachine.com/455_Long_Block.html


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## algershick (Oct 24, 2016)

Thanks! I could have provided more specifics. I pulled this motor out of a Bonneville, and I'm currently leaning toward a self learning EFI TBI over a carb, though I'm not 100% committed on that.


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## bigD (Jul 21, 2016)

algershick said:


> Thanks! I could have provided more specifics. I pulled this motor out of a Bonneville, and I'm currently leaning toward a self learning EFI TBI over a carb, though I'm not 100% committed on that.



Well, I'm a Q-jet guy. I know absolutely nothing about FI. But, there are probably some here who can help. :smile3:


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## PontiacJim (Dec 29, 2012)

The 061 heads are the first of the open chamber head design and they were used mid-year in the 1967 full sized cars. The '67 GTO still used the closed chamber 670 heads. They are somewhat unique. They have the A.I.R holes in the exhaust side, but poses no problem. The chamber roof is also lower than the later '68 and up heads and they are more like the RA IV chambers. Had a set I thought I was going to be able to use, but one head was cracked so could not use them - damn. 

Found this on another site: " the #061 , used on grocery getter 400s in 1967. I’m convinced that this head was the prototype for the later production open chamber heads, but the Pontiac engineers learned something on this head that they incorporated into all of the round port performance heads of the RA-II, IV, HO, and SD-455 heads. While the 061 still has the A.I.R. bosses in the exhaust ports, the chamber is the most open of any of the production heads. There is almost no ridge across the chamber, as two separate cuts were used during the machining process, and the spark plug hole is located in the highest possible portion of the chamber. In addition, the rear or squish wall of the chamber is laid back to a 60 degree angle, producing a true polyspherical chamber, with an absolute minimum of squish area. These heads have been ignored for years, primarily because they did not fit into any of the NHRA performance engines, and they had pressed in rocker studs. The A.I.R. bosses clog up the exhaust ports, and within the old non-porting rules of NHRA, nobody cared, but with some porting and screw-in studs, this head will knock your socks off. It doesn’t flow any better than any other D-port head, but the conversion of fuel to cylinder pressure is just as good as the RA-IV heads.”

Good heads to work with and do the upgrades as bigD outlined. :thumbsup:

Do the research on the EFI and compare. Read the complaints on all as I found some negative views on these type aftermarket products.


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## Pinion head (Jan 3, 2015)

Worked 061's are a great choice for a cast iron head for a strong 400 street/strip build. Nicest thing is you don't have to go looking for a set of cores. As mentioned above, the chambers are the first of Pontiacs open chamber design. Never milled, & ex valves not sunk, expect near 76cc chambers. A good street porting job, new stainless 1 piece.valves, a competition valve job, along with converting the pressed studs over to 7/16" screw in studs will make a really nice set of heads. Have had a set of worked 061's & have pulled 2 sets of cores for others wanting to go the same route. With today's very affordable custom pistons, like the AutoTecs, you should be able to spec a lightweight piston with a small dish & get static C/R down slightly. Not sure what octane gasoline is avail in your area, but I personally don't like fighting the ragid edge of detonation & usually concede a little static C/R so can run local 91 octane (no ethanol).


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