# 400 engine...any help appreciated



## mtgoat (May 28, 2013)

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Hello All. I am new to the forum and am just getting into this so i dont know a whole lot yet. I recently bought a 65 gto with a 1970 400 block in it. It has 1975 5C heads, edelbrock 600 cfm carb, stock intake, manifolds, etc and it is pretty weak. I do have an edelbrock performer intake, but not sure how much that will help without addressing other issues. I have not had a compression done on it yet. I have a budget right around 4k right now and was wondering if it is possible to get a lot more power (around 450) with this budget and what I have to work with.

I have a friend that recommended edelbrock heads which are spendy, but figure that my budget would be shot as I would probably need to redo/replace everything. I have looked around at some other cast/aluminum heads and am not sure which route to go. 

I want this car to be a daily driver with around 400-450 hp and be able to run on premium pump gas. 

I appreciate anyone and everyones help. Thanks.


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## Raymondpb (Jul 8, 2013)

With a 4k budget, you can reach 450 easy. For starters, get those heads!

Raymond


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## leeklm (Mar 11, 2012)

Problem is, the heads will eat up 1/2 of the $4K budget... And if the rest of the block is wore out with original pistons & rods, it will not make use of the good heads. Although you may need a little more than $4K to do this, I would look at the 461 stroker kits. your 5C heads would be perfect for 461 cubes, keeping compression just over 9.0 and pump gas friendly. With the right cam, you can make in the low 400hp range with the 5C heads and over 500 Lbs of Tq. When you can then afford to spend more, bolt those e-heads on the 461, and you will really have something!

Do a search through this forum on the 461 stroker motors, and you will find lots of good info.

Oh yeah, when you beef up the 400 or to a 461, you will need at least a 750 CFM qjet or holley.


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## BearGFR (Aug 25, 2008)

:agree Good advice

Bear


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## mtgoat (May 28, 2013)

Thanks for the info....I appreciate the help. I am going to see what I can find on the forum for 461 stroker motors.


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## mtgoat (May 28, 2013)

I have looked around at a lot of different 461 stroker kits, and the majority of them are right around $2,000. Does anyone know of a quality kit you can get for a better price? I do realize that 99% of the time you get what you pay for. Thanks for your help.


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## PontiacJim (Dec 29, 2012)

mtgoat said:


> I have looked around at a lot of different 461 stroker kits, and the majority of them are right around $2,000. Does anyone know of a quality kit you can get for a better price? I do realize that 99% of the time you get what you pay for. Thanks for your help.


OK, #1. This is a must for the learning curve here. Get a copy of Jim Hand's book "How To Build Max Performance Pontiac V-8's" from Amazon.com. You always want to build a Pontiac for torque over HP. You could begin with a 455 CI engine, build it with cast pistons, stock/reconditioned rods (SPS rod bolts), a torquey cam, 9.0 compression, basic head work. Keeping it at 5200 RPM and you won't need forged rods, forged pistons, or even the aluminum heads. Lower RPM's want higher velocity in the intake runners so to go bigger on the flow numbers pushed the engine RPM up higher in order to use them -now we need all the forged dollars. Same with a big cam, moves your power band higher and you have to spin more Rev's. Not needed with a Pontiac. You can also go the 400 CI block route and get an after market stroker crank to give you the 461 using either factory rod journals or chevy rod journals for aftermarket rods (back to 'mo money). Use the stroker crank will mean balancing everything ('mo money). Don't discount the 400 CI. Did an inexpensive build on my 400, all stock type pieces, a good torque cam, some old Offenhouser 360 intake I had lying around, a Q-Jet with adapter, and put a little money in the heads for stainless steel valves, good springs, 3 angle vavle job, and did my own port matching on the intake side with some mild polishing to blend -no big deal. Have a good dual exhaust with 3" pipes -used factory cast iron manifolds I port matched and polished. Fast with a lot of pull. No problems smoking tires. It would spin tight to 5,700 RPM and fall flat because of the cam I selected. Got about 16 MPG when my foot was out of it and I ran it sensibly on the highway.

Building an engine will yield you 100 different takes on how to do it. The factory GTO engine was rated at 360 HP with 10.75 compression. You don't want 10.75, you want between 8.5 -9.0 for the street, and it will still run hard. My engine is a 1972 using the 7K3 heads and its compression was in this range. No spark knock problems and I ran regular. The aluminum heads allow for 1 point more compression because they run cooler, but you use up a lot of doe. And remember, go too big on your build, and now you have to dole out some cash to beef up the rest of your drive line & suspension that you will be tearing up, just because the motor says it can.

Get Hand's book first! Many good listed engine build in the back of the book that tell you parts, HP, and estimated 1/4 times. Then decide. Research a little and get informed. Spend your money wisely and get the most HP for your buck. Lot of guys here to help. Good luck, and stash part of that budget money for a few sets of tires that you will be burning through. Yeah, I know, I ain't going to be smokin' my tires off. Yeah right, and I have a bridge in Brooklyn for sale. A toy in a kids hands just has to be played with. HaHaHa.


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## BearGFR (Aug 25, 2008)

I really recommend you don't scrimp on the rods. Here's the thing: rods have always been the weak link in these engines, even in stock form, and with a 461 we're talking about adding an additional full 1/2" to the stoke which increases the forces on the rods significantly.

Yes, you will occacionally find someone who has "run them forever with no problems spinning them to a bazillion rpm", but I promise you, for every one person like that you find, there'll be hundreds of others who tried it and lost the whole engine when one of the rods let go. My opinion is that it's just not worth the risk involved, especially when you consider that the price you'll pay for a *quality* recondition job will come very close to the purchase price of a good set of forged H-beams anyway... and you'll still just have factory rods. Rods that you'll worry about every time you put your foot in it, or some ricer decides to "try on grandpa" and maybe you push it just a little bit past your self-imposed red-line sweating bullets the whole time, or that force you to artificially "ham string" the engine and prevent it from producing all the power and torque it's capable of. 

Tell the truth now - if you were willing to religiously limit yourself on power like that then why would you be thinking about building a stroker in the first place? 

If you have to scrimp on cost, do it smewhere else in an area that's not so important (or so risky).

Just last year, I was making a pass in the Beast at the track. When it shifted to high, the direct clutch let go and let the motor rev half-way to Pluto before I could wrap my mind around what had happened and out of the throttle. (My rev-limiter had gone bad on me and I hadn't replaced it yet.) You can bet I was sure happy I had good rods in it when that happened.

Bear


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## geeteeohguy (Feb 2, 2008)

Yes, yes, yes. By the time you compare the cost of reconditioned stock cast rods to the aftermarket good stuff, you are only about $100 difference. Cut cost _anywhere_ but the rods. I have stock rods in both of my GTO's, only because in the early-mid '80's when I did the engines, nothing else was available. You can bet I wouldn't use them on any rebuild I did now. I had the ones in the '65 shot peened, magnefluxed, balanced, and polished....and the engine has seen 'to the moon' revs and valve-float speed shifts in my earlier days, but I think I've been moe lucky than anything else. I have seen mountains of blown up Pontiac blocks over the decades due to a single rod letting go. Don't chance it.


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