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2 Engines Similar Results

68Chevele

Veteran Member
Senior Member
After watching some of my in car race videos last night I notice something with the 2 pump gas engines I ran last year.

Engine A is a .040 350 SBC flat top piston 9.75:1 compression
.600 lift roller cam with all related hardware
Mild ported Sportsman II 200cc heads
Modified Eddy Air Gap
850 FST VS
1 3/4 Hooker S/C headers
Best time was
1.55 60ft.
7.16 1/8 mile @95 mph
11.30@117.82 mph 1/4 mile with 4.88 gear and my 10" TCI race converter 72° day

Engine B is a .030 flat top piston 461 BBC 7.95:1 compression
Crower flat tappet (solid) .543/.595 243°/ 250° on a 106 lca
Ported 360 peanut port heads with 2.19 and 1.88 valves
Eddy Air Gap, 1000 Race Demon carb
1 3/4" headers
Best time was 1.52 60ft
7.04 1/8 @96mph
11.16@118mph 4.10 gear with my 8" TCI race converter 83° day

It is very surprising that the 2 engines one with over 100 cubes more with the bigger engine only having a slight advantage. I think with the 8" converter the 358 will be right on par with the 461. I love testing stuff like this as it does surprise people that the little engine can hang that well with the bigger stuff but it's all about the combination and nothing more. Future mods to these 2 engines are,

Ported L-29 Gen VI heads (on the engine now, 1 7/8" headers, 3.73 gearing and test out the FST 850 on the 461 BBC

Changes on the 358 are 8" converter, use the Ported Victor Jr. or my (don't laugh) ported old school "torker" intake manifold and possibly 2 different sets of heads.

Goal is to get both of these in the high 10's running on pump gas.

Then there's the Vortec 406 I ran in the high 10's back in 2019 just waiting to have the AFR heads and a roller cam test in that engine.
 
That's the best kind of apple to piss people off at the race track.
I'm guilty of making less than optimal component choices. My 565 would be an example of that. It does well with the current combo but it could have made considerably more power with different heads and intake. I simply didn't want to change my intake.
 
I'm guilty of making less than optimal component choices. My 565 would be an example of that. It does well with the current combo but it could have made considerably more power with different heads and intake. I simply didn't want to change my intake.
What do you have on the 565 now and what does it run?
 
What do you have on the 565 now and what does it run?
Using AFR 300 cc Roval port heads. Car ran 9.55@141.5 spinning off starting line.
I think it might have been good for a 9.40 had it hooked. 60' was a 1.39 0n that pass and it has been 1.301 60'
3800lb driver kinda. Made 900.7 hp at 6700 to 7100 and 760lbft flat as a pancake (almost flat) lol
 
Using AFR 300 cc Roval port heads. Car ran 9.55@141.5 spinning off starting line.
I think it might have been good for a 9.40 had it hooked. 60' was a 1.39 0n that pass and it has been 1.301 60'
3800lb driver kinda. Made 900.7 hp at 6700 to 7100 and 760lbft flat as a pancake (almost flat) lol
That's very impressive with those heads and I remember Hot Rod testing the Magnum AFR 300 heads against a lot of larger port heads making less power. I think you made a pretty good choice with those heads. What trans and converter did you use? I could see that combo working well with a P/G trans to keeping the wheel spin down.
 
That's very impressive with those heads and I remember Hot Rod testing the Magnum AFR 300 heads against a lot of larger port heads making less power. I think you made a pretty good choice with those heads. What trans and converter did you use? I could see that combo working well with a P/G trans to keeping the wheel spin down.
Powerglide would favor a lighter car perhaps. I've run in the 5.90's 1/8th mile @ 116 on both a 28x10.5 slick and on a 28" pro bracket radial. The radial is a tick quicker but not as forgiving on a mediocre track.
I use a grid for ignition timing, launch rpms etc and for shift rpm's and a shifnoid for shift control with an FTI th400and convrter (4500 stall) with a 12 bolt. I went with an ATI Supercase because it's not the nightmare that is a certain brand trans shield that has to be modified to fit. Plus the case doesn't need a blanket. The car is a very much intactpretty nice SS excepting ther hood. I have the original 396 still but the original glide is long gone. I personally got rid of it back in 1980 when the car belonged to a friend. I have the 565 out right now and a 499 inch pump gas piece in it now. It has Edelbrock "performer" Rovals on it and it also has a Dart intake. It ran 6.44 @ 106 first nite out which I figure to be a 10.11 1/4 pass. I took the Dart from it to put on the 565 so that's why I went with the AFR 300's. This was an effort a couple thought I was nuts to do but my old head porter "RIP" Roger Helgesen tried to talk me out of even though he said it was likely the limit but then he got very I"ll and could no longer do any port work so I contacted Tony Mamo, explained what I was up to, asked for his assistance, he was game to do it altough he had some reservation but he performed his work on the heads and we went to Westech for the dyno session. First ime the engine struggled to make power so I took it home, I had used a well known machinist for some work which was sub par and disappointing so I took it apart, Had to rebush the too tight lifter bores and had a different type piston made "same manufacturer just better piston" and ring set and went back to the dyno. Went with total seal gapless second time. Tony met me there again and it met expectation beyond what he though it would make. It worked out well so I bought him lunch. We got some print on the piece and I have it somewhere but it pumped up Tony a little Lol
One thing about this hobby is that we meet some very talented and willing to help people if we approach them as normal advocates with the desire to learn'. Mamo is a good man.
Cept he got off on the LS critter path. His driver Caddy hauls ass. long write but hope it helps someone. Knowing what I know I'd use a larger head, likely in the 360cc range more rpms and would srutinize the induction system overall. We can build a 3500 horsepower engine but now it has to work in whatever car we plopped it in. Boiled down to combination combination or combination.
 
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Do you think the gear change to 3.73 will hurt?
On what car? If you mean my car, yes I think it "might" hurt the entire pass. With 4.11's it crossed the stripe at 7100 rpms. Focus on weight transfer, shock settings, tire pressure, timing curve etc would be more revealing.. That requires a day of testing with few cars at the track. We are very limited here in soCal on a real track.
If you are referring to another car I am unaware of which car.
 
I thought I read 68Chevelle changed rear gears to 3.73's ?
That's the plan when I build my other 8.5 rear end. The 3.73's will help the bigger engine go down the track better as last years 406 did not like the 4.88's and I am sure my peanut port engine would not like it as well. I first leaned the car was over geared when I put the 30X9's on the car and the ET picked right up over the 28" tires and the 28's sit in the basement until I order the new tires for fall racing this year. No more tire chatter for me, I am going with the M/T pro drag radials now over the Hoosiers.
 
Are you figuring the 3.73 better for the 1/4 on your car? Just asking because the engine builder that built my BB short block said my 3.73 wouldn't be good for the local 1/8 track
 
Are you figuring the 3.73 better for the 1/4 on your car? Just asking because the engine builder that built my BB short block said my 3.73 wouldn't be good for the local 1/8 track
No the 4.10 gear in the car before I busted the rear end with the 28" tire made the 468 PP engine stop pulling at around 1100ft. after swapping the tires I knew it was too much gear. With big torque engine you need to let them pull you down the track, not RPM to death down the track. Now the little 358 SBC likes those 4.88's as I found out last fall, now I want to see if that engine will like that Vic Jr. my friend just tested out so that's going on the engine as he don't like my porting price.
 
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